You searched for +publisher:"Virginia Tech" +contributor:("Rakha, Hesham A.").
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1.
Reinsel, Samuel Joseph.
Drive Quality Improvement and Calibration of a Post-Transmission Parallel Hybrid Electric Vehicle.
Degree: MS, Mechanical Engineering, 2018, Virginia Tech
URL: http://hdl.handle.net/10919/85046 
► The Hybrid Electric Vehicle Team (HEVT) of Virginia Tech is one of 16 university teams participating in EcoCAR 3, the latest competition in the Advanced…
(more)
▼ The Hybrid Electric Vehicle Team (HEVT) of
Virginia Tech is one of 16 university teams participating in EcoCAR 3, the latest competition in the Advanced Vehicle Technology Competitions (AVTC) organized by Argonne National Labs. EcoCAR 3 tasks teams with converting a 2016 Chevrolet Camaro into a hybrid electric vehicle with 5 main goals: reducing petroleum energy use and greenhouse gas emissions while maintaining safety, performance, and consumer acceptability. Over the last 4 years, HEVT has designed and built a plugin parallel hybrid electric vehicle with a unique powertrain architecture. This work deals with utilizing the unique powertrain layout of the HEVT Camaro to improve drive quality, a key component in consumer acceptability. Although there are many ways to approach drive quality, most aspects can be analyzed in the smoothness of the vehicle longitudinal acceleration response.
This research is focused on improving the drive quality of the vehicle developed for EcoCAR 3. Multiple algorithms are developed to address specific aspects of drive quality that can only be done with the powertrain developed. This begins by researching the control strategies used in modern automatic transmissions, and moves into the modeling strategy used to begin algorithm development. Two main strategies are developed and calibrated in the vehicle. The first being a strategy for reducing jerk in pure electric mode by limiting motor torque response. The second strategy aims to improve transmission shift quality by using the electric motor to reduce torque fluctuations at the driveshaft. The energy consumption impact of both of these strategies is also analyzed to ensure that drive quality does not come at the large expense of energy consumption.
Advisors/Committee Members: Nelson, Douglas J. (committeechair), Southward, Steve C. (committee member), Rakha, Hesham A. (committee member).
Subjects/Keywords: Hybrid Electric Vehicle; P3 parallel; drive quality; automatic transmission; automotive
…HEVT) of Virginia Tech is one of 16 university teams
participating in EcoCAR 3, the…
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APA (6th Edition):
Reinsel, S. J. (2018). Drive Quality Improvement and Calibration of a Post-Transmission Parallel Hybrid Electric Vehicle. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/85046
Chicago Manual of Style (16th Edition):
Reinsel, Samuel Joseph. “Drive Quality Improvement and Calibration of a Post-Transmission Parallel Hybrid Electric Vehicle.” 2018. Masters Thesis, Virginia Tech. Accessed February 28, 2021.
http://hdl.handle.net/10919/85046.
MLA Handbook (7th Edition):
Reinsel, Samuel Joseph. “Drive Quality Improvement and Calibration of a Post-Transmission Parallel Hybrid Electric Vehicle.” 2018. Web. 28 Feb 2021.
Vancouver:
Reinsel SJ. Drive Quality Improvement and Calibration of a Post-Transmission Parallel Hybrid Electric Vehicle. [Internet] [Masters thesis]. Virginia Tech; 2018. [cited 2021 Feb 28].
Available from: http://hdl.handle.net/10919/85046.
Council of Science Editors:
Reinsel SJ. Drive Quality Improvement and Calibration of a Post-Transmission Parallel Hybrid Electric Vehicle. [Masters Thesis]. Virginia Tech; 2018. Available from: http://hdl.handle.net/10919/85046
2.
Aljamal, Mohammad Abdulraheem.
Comparison of Microscopic and Mesoscopic Traffic Modeling Tools for Evacuation Analysis.
Degree: MS, Civil Engineering, 2017, Virginia Tech
URL: http://hdl.handle.net/10919/79592
► Evacuation processes can be evaluated using different simulation models. However, recently, microscopic simulation models have become a more popular tool for this purpose. The objectives…
(more)
▼ Evacuation processes can be evaluated using different simulation models. However, recently, microscopic simulation models have become a more popular tool for this purpose. The objectives of this study are to model multiple evacuation scenarios and to compare the INTEGRATION microscopic traffic simulation model against the MATSim mesoscopic model. Given that the demand was the same for both models, the comparison was achieved based on three indicators: estimated evacuation time, average trip duration, and average trip distance. The results show that the estimated evacuation times in both models are close to each other since the Origin-Destination input file has a long tail distribution and so the majority of the evacuation time is associated when travelers evacuate and not the actual evacuation times. However, the evaluation also shows a considerable difference between the two models in the average trip duration. The average trip duration using INTEGRATION increases with increasing traffic demand levels and decreasing roadway capacity. On the other hand, the average trip duration using MATSim decreases with increasing traffic demand and decreasing the roadway capacity. Finally, the average trip distance values were significantly different in both models. The conclusion showed that the INTEGRATION model is more realistic than the MATSim model for evacuation purposes. The study concludes that despite the large execution times of a microscopic traffic simulation, the use of microsimulation is a worthwhile investment.
Advisors/Committee Members: Rakha, Hesham A. (committeechair), Pamela Marie Murray-Tuite (committee member), Jianhe Du (committee member).
Subjects/Keywords: Evacuation Modeling; Microscopic Simulation; Disaster; Demand; Mesoscopic
…developed by the Center for Sustainable
Mobility (CSM) at the Virginia Tech… …x29; at the Virginia Tech
Transportation Institute (VTTI). INTEGRATION was…
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APA (6th Edition):
Aljamal, M. A. (2017). Comparison of Microscopic and Mesoscopic Traffic Modeling Tools for Evacuation Analysis. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/79592
Chicago Manual of Style (16th Edition):
Aljamal, Mohammad Abdulraheem. “Comparison of Microscopic and Mesoscopic Traffic Modeling Tools for Evacuation Analysis.” 2017. Masters Thesis, Virginia Tech. Accessed February 28, 2021.
http://hdl.handle.net/10919/79592.
MLA Handbook (7th Edition):
Aljamal, Mohammad Abdulraheem. “Comparison of Microscopic and Mesoscopic Traffic Modeling Tools for Evacuation Analysis.” 2017. Web. 28 Feb 2021.
Vancouver:
Aljamal MA. Comparison of Microscopic and Mesoscopic Traffic Modeling Tools for Evacuation Analysis. [Internet] [Masters thesis]. Virginia Tech; 2017. [cited 2021 Feb 28].
Available from: http://hdl.handle.net/10919/79592.
Council of Science Editors:
Aljamal MA. Comparison of Microscopic and Mesoscopic Traffic Modeling Tools for Evacuation Analysis. [Masters Thesis]. Virginia Tech; 2017. Available from: http://hdl.handle.net/10919/79592
Virginia Tech
3.
Lucic, Ivana.
Truck Modeling Along Grade Sections.
Degree: MS, Civil Engineering, 2001, Virginia Tech
URL: http://hdl.handle.net/10919/32842
► This research effort first characterizes the trucks traveling along US highways by analyzing data from Interstate 81. It is hypothesized that I-81 is typical of…
(more)
▼ This research effort first characterizes the trucks traveling along US highways by analyzing data from Interstate 81. It is hypothesized that I-81 is typical of US highways and thus can provide some insight into typical truck characteristics. These truck characteristics are important for the development of an exhaustive vehicle performance procedure. Analysis was done based on data collected at the Troutville weigh station. The characterization involves an analysis of vehicle class distribution, GVW (Gross Vehicle Weight) distribution, vehicle volume distribution, Average Weight on Tractive Axle (AWTA), and typical weight-to-power ratios. The thesis then assembles a database of systematic field data that can be utilized for the validation of vehicle performance models. This database is unique because it was conducted in a controlled field environment where the vehicle is only constrained by its dynamics. Using the assembled field database, a simple constant power vehicle dynamics model for estimating maximum vehicle acceleration levels based on a vehicle's tractive effort and aerodynamic, rolling, and grade resistance forces was tested and validated. In addition, typical model input parameters for different vehicle, pavement, and tire characteristics are included in the thesis. The model was found to predict vehicle speeds at the conclusion of the travel along the section to within 5 km/h (3.1 mi/h) of field measurements, thus demonstrating the validity and applicability of the model. Finally, the research effort introduces the concept of variable power in order to enhance current state-of-the-art vehicle dynamics models and capture the build-up of power as a vehicle engages in gearshifts at low travel speeds. The proposed enhancement to the current state-of-practice vehicle dynamics model allows the model to reflect typical vehicle acceleration behavior more accurately. Subsequently, the model parameters are calibrated using field measurements along a test roadway facility.
Advisors/Committee Members: Rakha, Hesham A. (committeechair).
Subjects/Keywords: Traffic flow theory; Truck modeling; Vehicle dynamics; Traffic modeling
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APA (6th Edition):
Lucic, I. (2001). Truck Modeling Along Grade Sections. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/32842
Chicago Manual of Style (16th Edition):
Lucic, Ivana. “Truck Modeling Along Grade Sections.” 2001. Masters Thesis, Virginia Tech. Accessed February 28, 2021.
http://hdl.handle.net/10919/32842.
MLA Handbook (7th Edition):
Lucic, Ivana. “Truck Modeling Along Grade Sections.” 2001. Web. 28 Feb 2021.
Vancouver:
Lucic I. Truck Modeling Along Grade Sections. [Internet] [Masters thesis]. Virginia Tech; 2001. [cited 2021 Feb 28].
Available from: http://hdl.handle.net/10919/32842.
Council of Science Editors:
Lucic I. Truck Modeling Along Grade Sections. [Masters Thesis]. Virginia Tech; 2001. Available from: http://hdl.handle.net/10919/32842
4.
Calle Laguna, Alvaro Jesus.
Isolated Traffic Signal Optimization Considering Delay, Energy, and Environmental Impacts.
Degree: MS, Civil Engineering, 2017, Virginia Tech
URL: http://hdl.handle.net/10919/74238
► Traffic signal cycle lengths are traditionally optimized to minimize vehicle delay at intersections using the Webster formulation. This thesis includes two studies that develop new…
(more)
▼ Traffic signal cycle lengths are traditionally optimized to minimize vehicle delay at intersections using the Webster formulation. This thesis includes two studies that develop new formulations to compute the optimum cycle length of isolated intersections, considering measures of effectiveness such as vehicle delay, fuel consumption and tailpipe emissions. Additionally, both studies validate the Webster model against simulated data. The microscopic simulation software, INTEGRATION, was used to simulate two-phase and four-phase isolated intersections over a range of cycle lengths, traffic demand levels, and signal timing lost times. Intersection delay, fuel consumption levels, and emissions of hydrocarbon (HC), carbon monoxide (CO), oxides of nitrogen (NOx), and carbon dioxide (CO2) were derived from the simulation software. The cycle lengths that minimized the various measures of effectiveness were then used to develop the proposed formulations. The first research effort entailed recalibrating the Webster model to the simulated data to develop a new delay, fuel consumption, and emissions formulation. However, an additional intercept was incorporated to the new formulations to enhance the Webster model. The second research effort entailed updating the proposed model against four study intersections. To account for the stochastic and random nature of traffic, the simulations were then run with twenty random seeds per scenario. Both efforts noted its estimated cycle lengths to minimize fuel consumption and emissions were longer than cycle lengths optimized for vehicle delay only. Secondly, the simulation results manifested an overestimation in optimum cycle lengths derived from the Webster model for high vehicle demands.
Advisors/Committee Members: Rakha, Hesham A. (committeechair), Du, Jianhe (committee member), Katz, Bryan J. (committee member).
Subjects/Keywords: Traffic Signal Control Systems; Signal Optimization; Microsimulation; Fuel Consumption Modeling; Greenhouse Gases Modeling
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APA (6th Edition):
Calle Laguna, A. J. (2017). Isolated Traffic Signal Optimization Considering Delay, Energy, and Environmental Impacts. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/74238
Chicago Manual of Style (16th Edition):
Calle Laguna, Alvaro Jesus. “Isolated Traffic Signal Optimization Considering Delay, Energy, and Environmental Impacts.” 2017. Masters Thesis, Virginia Tech. Accessed February 28, 2021.
http://hdl.handle.net/10919/74238.
MLA Handbook (7th Edition):
Calle Laguna, Alvaro Jesus. “Isolated Traffic Signal Optimization Considering Delay, Energy, and Environmental Impacts.” 2017. Web. 28 Feb 2021.
Vancouver:
Calle Laguna AJ. Isolated Traffic Signal Optimization Considering Delay, Energy, and Environmental Impacts. [Internet] [Masters thesis]. Virginia Tech; 2017. [cited 2021 Feb 28].
Available from: http://hdl.handle.net/10919/74238.
Council of Science Editors:
Calle Laguna AJ. Isolated Traffic Signal Optimization Considering Delay, Energy, and Environmental Impacts. [Masters Thesis]. Virginia Tech; 2017. Available from: http://hdl.handle.net/10919/74238
5.
Almutairi, Fawaz.
Eco-cooperative adaptive cruise control at multiple signalized intersections.
Degree: MS, Civil Engineering, 2017, Virginia Tech
URL: http://hdl.handle.net/10919/84351
► Consecutive traffic signals produce vehicle stops and acceleration/deceleration maneuvers on arterial roads, which may increase vehicle fuel consumption levels significantly. Eco-cooperative adaptive cruise control (Eco-CACC)…
(more)
▼ Consecutive traffic signals produce vehicle stops and acceleration/deceleration maneuvers on arterial roads, which may increase vehicle fuel consumption levels significantly. Eco-cooperative adaptive cruise control (Eco-CACC) systems can improve vehicle energy efficiency using connected vehicle (CV) technology. In this thesis, an Eco-CACC system is proposed to compute a fuel-optimized vehicle trajectory while traversing multiple signalized intersections. The proposed system utilizes signal phasing and timing (SPaT) information together with real-time vehicle dynamics data to compute the optimal acceleration/deceleration levels and cruise speeds for connected-technology-equipped vehicles while approaching and leaving signalized intersections, while considering vehicle queues upstream of the intersections. The INTEGRATION microscopic traffic simulation software was used to conduct a comprehensive sensitivity analysis of a set of variables, including different levels of CV market penetration rates (MPRs), demand levels, phase splits, offsets, and distances between intersections to assess the benefits of the proposed algorithm. Based on the analysis, fuel consumption saving increase with an increase in MPRs and a decrease in the cycle length. At a 100% equipped-vehicle MPR, the fuel consumption is reduced by as much as 13.8% relative to the base no Eco-CACC control. The results demonstrate an existence of optimal values for demand levels and the distance between intersections to reach the maximum fuel consumption reduction. Moreover, if the offset is near the optimal values for that specific approach, the benefits from the algorithm are reduced. The algorithm is limited to under-saturated conditions, so the algorithm should be enhanced to deal with over-saturated conditions.
Advisors/Committee Members: Rakha, Hesham A. (committeechair), Hancock, Kathleen L. (committee member), Yang, Hao (committee member).
Subjects/Keywords: Eco-CACC; multiple intersections; signal phasing and timing; vehicle queue; fuel consumption; INTEGRATION
…Virginia Tech Comprehensive Power-based Fuel Model (VT-CPFM) is used in this
study as… …Bulck, "Virginia Tech
Comprehensive Power-Based Fuel Consumption Model: Model development… …Ahn, K. Moran, B. Saerens, and E. V. d. Bulck, "Virginia Tech
Comprehensive Power-Based…
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APA (6th Edition):
Almutairi, F. (2017). Eco-cooperative adaptive cruise control at multiple signalized intersections. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/84351
Chicago Manual of Style (16th Edition):
Almutairi, Fawaz. “Eco-cooperative adaptive cruise control at multiple signalized intersections.” 2017. Masters Thesis, Virginia Tech. Accessed February 28, 2021.
http://hdl.handle.net/10919/84351.
MLA Handbook (7th Edition):
Almutairi, Fawaz. “Eco-cooperative adaptive cruise control at multiple signalized intersections.” 2017. Web. 28 Feb 2021.
Vancouver:
Almutairi F. Eco-cooperative adaptive cruise control at multiple signalized intersections. [Internet] [Masters thesis]. Virginia Tech; 2017. [cited 2021 Feb 28].
Available from: http://hdl.handle.net/10919/84351.
Council of Science Editors:
Almutairi F. Eco-cooperative adaptive cruise control at multiple signalized intersections. [Masters Thesis]. Virginia Tech; 2017. Available from: http://hdl.handle.net/10919/84351
6.
Conran, Charles Arthur.
Modeling Microscopic Driver Behavior under Variable Speed Limits: A Driving Simulator and Integrated MATLAB-VISSIM Study.
Degree: MS, Civil Engineering, 2017, Virginia Tech
URL: http://hdl.handle.net/10919/78234
► Variable speed limits (VSL) are dynamic traffic management systems designed to increase the efficiency and safety of highways. While the macroscopic performance of VSL systems…
(more)
▼ Variable speed limits (VSL) are dynamic traffic management systems designed to increase the efficiency and safety of highways. While the macroscopic performance of VSL systems is well explored in the existing literature, there is a need to further understand the microscopic behavior of vehicles driving in VSL zones. Specifically, driver compliance to advisory VSL systems is quantified based on a driving-simulation experiment and introduced into a broader microscopic behavior model. Statistical analysis indicates that VSL compliance can be predicted based upon several VSL design parameters. The developed two-state microscopic model is calibrated to driving-simulation trajectory data. A calibrated VSL microscopic model can be utilized for new VSL control and macroscopic performance studies, adding an increased dimension of realism to simulation work. As an example, the microscopic model is implemented within VISSIM (overriding the default car-following model) and utilized for a safety-mobility performance assessment of an incident-responsive VSL control algorithm implemented in a MATLAB COM interface. Examination of the multi-objective optimization frontier reveals an inverse relationship between safety and mobility under different control algorithm parameters. Engineers are thus faced with a decision between performing multi-objective optimization and selecting a dominant VSL control objective (e.g. maximizing safety versus mobility performance).
Advisors/Committee Members: Abbas, Montasir M. (committeechair), Hotle, Susan (committee member), Rakha, Hesham A. (committee member).
Subjects/Keywords: Microscopic Driving Behavior; Variable Speed Limits; Traffic Simulation
…would like to thank Virginia Tech for the use of its driving simulator that
made this research… …utilizing the Drive-Safety DS-250
model (Figure 1) located on the campus of Virginia… …Tech. Based on the conducted literature
synthesis, the authors settled on three control…
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APA (6th Edition):
Conran, C. A. (2017). Modeling Microscopic Driver Behavior under Variable Speed Limits: A Driving Simulator and Integrated MATLAB-VISSIM Study. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/78234
Chicago Manual of Style (16th Edition):
Conran, Charles Arthur. “Modeling Microscopic Driver Behavior under Variable Speed Limits: A Driving Simulator and Integrated MATLAB-VISSIM Study.” 2017. Masters Thesis, Virginia Tech. Accessed February 28, 2021.
http://hdl.handle.net/10919/78234.
MLA Handbook (7th Edition):
Conran, Charles Arthur. “Modeling Microscopic Driver Behavior under Variable Speed Limits: A Driving Simulator and Integrated MATLAB-VISSIM Study.” 2017. Web. 28 Feb 2021.
Vancouver:
Conran CA. Modeling Microscopic Driver Behavior under Variable Speed Limits: A Driving Simulator and Integrated MATLAB-VISSIM Study. [Internet] [Masters thesis]. Virginia Tech; 2017. [cited 2021 Feb 28].
Available from: http://hdl.handle.net/10919/78234.
Council of Science Editors:
Conran CA. Modeling Microscopic Driver Behavior under Variable Speed Limits: A Driving Simulator and Integrated MATLAB-VISSIM Study. [Masters Thesis]. Virginia Tech; 2017. Available from: http://hdl.handle.net/10919/78234
Virginia Tech
7.
Edwardes, William Andrew.
Modeling Diesel Bus Fuel Consumption and Dynamically Optimizing Bus Scheduling Efficiency.
Degree: MS, Civil Engineering, 2014, Virginia Tech
URL: http://hdl.handle.net/10919/49707
► There are currently very few models that estimate diesel and hybrid bus fuel consumption levels. Those that are available either require significant dynamometer data gathering…
(more)
▼ There are currently very few models that estimate diesel and hybrid bus fuel consumption levels. Those that are available either require significant dynamometer data gathering to calibrate the model parameters and also produce a bang-bang control system (optimum control entails maximum throttle and braking input). This thesis extends the
Virginia Tech Comprehensive Power-Based Fuel Consumption Model (VT-CPFM) to model diesel buses and develops an application for it. A procedure is developed to calibrate the bus parameters using publicly available data from the Altoona Bus Research and Testing Center. In addition, calibration is also made using in-field bus fuel consumption data. The research presented in this thesis calibrates model parameters for a total of 10 standard diesel buses and 3 hybrid buses from Altoona and 10 buses from Blacksburg Transit. In the case of the Altoona data, the VT-CPFM estimated fuel consumption levels on the Orange County bus cycle dynamometer test produce an average error of 4.7%. The estimation error is less than 6% for all but two buses with a maximum error of 10.66% for one hybrid bus. The VT-CPFM is also validated using on-road fuel consumption measurements that are derived by creating drive cycles from acceleration information producing an average estimation error of 22%. These higher errors are attributed to the errors associated with constructing the in-field drive cycles given that they are not available. In the case of the Blacksburg Transit buses, the calibrated parameters produce a low sum of mean squared error, less than 0.002, and a coefficient of determination greater than 0.93. Finally an application of the VT-CPFM is presented in the form of a dynamic bus scheduling algorithm.
Advisors/Committee Members: Rakha, Hesham A. (committeechair), Nelson, Douglas J. (committee member), Elshawarby, Ihab E. (committee member).
Subjects/Keywords: Transit Bus Fuel Consumption; Dynamic Bus Scheduling; Transit Bus; Fuel Consumption Modeling; VT-CPFM
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APA (6th Edition):
Edwardes, W. A. (2014). Modeling Diesel Bus Fuel Consumption and Dynamically Optimizing Bus Scheduling Efficiency. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/49707
Chicago Manual of Style (16th Edition):
Edwardes, William Andrew. “Modeling Diesel Bus Fuel Consumption and Dynamically Optimizing Bus Scheduling Efficiency.” 2014. Masters Thesis, Virginia Tech. Accessed February 28, 2021.
http://hdl.handle.net/10919/49707.
MLA Handbook (7th Edition):
Edwardes, William Andrew. “Modeling Diesel Bus Fuel Consumption and Dynamically Optimizing Bus Scheduling Efficiency.” 2014. Web. 28 Feb 2021.
Vancouver:
Edwardes WA. Modeling Diesel Bus Fuel Consumption and Dynamically Optimizing Bus Scheduling Efficiency. [Internet] [Masters thesis]. Virginia Tech; 2014. [cited 2021 Feb 28].
Available from: http://hdl.handle.net/10919/49707.
Council of Science Editors:
Edwardes WA. Modeling Diesel Bus Fuel Consumption and Dynamically Optimizing Bus Scheduling Efficiency. [Masters Thesis]. Virginia Tech; 2014. Available from: http://hdl.handle.net/10919/49707
Virginia Tech
8.
Moniot, Matthew Louis.
Path Selection to Minimize Energy Consumption of an Electric Vehicle using Synthetic Speed Profiles and Predictive Terminal Energy.
Degree: MS, Mechanical Engineering, 2017, Virginia Tech
URL: http://hdl.handle.net/10919/78223
► Manufacturers of passenger vehicles are experiencing increased pressure from consumers and legislators due to the impact of transportation on the environment. Automotive manufacturers are responding…
(more)
▼ Manufacturers of passenger vehicles are experiencing increased pressure from consumers and legislators due to the impact of transportation on the environment. Automotive manufacturers are responding by designing more sustainable forms of transportation through a variety of efforts, including increased vehicle efficiency and the electrification of vehicle powertrains (plug in hybrid electric vehicles (PHEV) and battery electric vehicles (BEV)). An additional method for reducing the environmental impact of personal transport is eco-routing, a methodology which selects routes on the basis of energy consumption.
Standard navigation systems offer route alternatives between a user clarified origin and destination when there are multiple paths available. These alternatives are commonly weighted on the basis of minimizing either total travel time (TTT) or trip distance. Eco-routing offers an alternative criterion – minimizing route energy consumption. Calculation of the energy consumption of a route necessitates the creation of a velocity profile which models how the route will be driven and a powertrain model which relates energy consumption to the constructed velocity profile. Existing research efforts related to both of these aspects typically require complex analysis and proprietary vehicle properties.
A new approach to weighting the energy consumption of different routes is presented within this paper. The process of synthesizing velocity profiles is an improvement upon simpler models while requiring fewer variables as compared to more complex models. A single input, the maximum acceleration, is required to tune driver aggressiveness throughout an entire route. Additionally, powertrain results are simplified through the application of a new parameter, predictive terminal energy. The parameter uses only glider properties as inputs, as compared to dedicated powertrain models which use proprietary vehicle information as inputs which are not readily available from manufacturers. Application of this research reduces computation time and increases the number of vehicles for which this analysis can be applied. An example routing scenario is presented, demonstrating the capability of the velocity synthesis and predictive terminal energy methodologies.
Advisors/Committee Members: Nelson, Douglas J. (committeechair), Rakha, Hesham A. (committee member), West, Robert L. (committee member).
Subjects/Keywords: eco-routing; battery electric vehicle; acceleration models; velocity profiles; environment; energy consumption
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APA (6th Edition):
Moniot, M. L. (2017). Path Selection to Minimize Energy Consumption of an Electric Vehicle using Synthetic Speed Profiles and Predictive Terminal Energy. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/78223
Chicago Manual of Style (16th Edition):
Moniot, Matthew Louis. “Path Selection to Minimize Energy Consumption of an Electric Vehicle using Synthetic Speed Profiles and Predictive Terminal Energy.” 2017. Masters Thesis, Virginia Tech. Accessed February 28, 2021.
http://hdl.handle.net/10919/78223.
MLA Handbook (7th Edition):
Moniot, Matthew Louis. “Path Selection to Minimize Energy Consumption of an Electric Vehicle using Synthetic Speed Profiles and Predictive Terminal Energy.” 2017. Web. 28 Feb 2021.
Vancouver:
Moniot ML. Path Selection to Minimize Energy Consumption of an Electric Vehicle using Synthetic Speed Profiles and Predictive Terminal Energy. [Internet] [Masters thesis]. Virginia Tech; 2017. [cited 2021 Feb 28].
Available from: http://hdl.handle.net/10919/78223.
Council of Science Editors:
Moniot ML. Path Selection to Minimize Energy Consumption of an Electric Vehicle using Synthetic Speed Profiles and Predictive Terminal Energy. [Masters Thesis]. Virginia Tech; 2017. Available from: http://hdl.handle.net/10919/78223
Virginia Tech
9.
Zhang, Dengfeng.
Latent Class Model in Transportation Study.
Degree: PhD, Statistics, 2015, Virginia Tech
URL: http://hdl.handle.net/10919/51203
► Statistics, as a critical component in transportation research, has been widely used to analyze driver safety, travel time, traffic flow and numerous other problems. Many…
(more)
▼ Statistics, as a critical component in transportation research, has been widely used to analyze driver safety, travel time, traffic flow and numerous other problems. Many of these popular topics can be interpreted as to establish the statistical models for the latent structure of data. Over the past several years, the interest in latent class models has continuously increased due to their great potential in solving practical problems. In this dissertation, I developed several latent class models to quantitatively analyze the hidden structure of transportation data and addressed related application issues.
The first model is focused on the uncertainty of travel time, which is critical for assessing the reliability of transportation systems. Travel time is random in nature, and contains substantial variability, especially under congested traffic conditions. A Bayesian mixture model, with the ability to incorporate the influence from covariates such as traffic volume, has been proposed. This model advances the previous multi-state travel time reliability model in which the relationship between response and predictors was lacking.
The Bayesian mixture travel time model, however, lack the power to accurately predict the future travel time. The analysis indicates that the independence assumption, which is difficult to justify in real data, could be a potential issue. Therefore, I proposed a Hidden Markov model to accommodate dependency structure, and the modeling results were significantly improved.
The second and third parts of the dissertation focus on the driver safety identification. Given the demographic information and crash history, the number of crashes, as a type of count data, is commonly modeled by Poisson regression. However, the over-dispersion issue within the data implies that a single Poisson distribution is insufficient to depict the substantial variability. Poisson mixture model is proposed and applied to identify risky and safe drivers. The lower bound of the estimated misclassification rate is evaluated using the concept of overlap probability. Several theoretical results have been discussed regarding the overlap probability. I also introduced quantile regression based on discrete data to specifically model the high-risk drivers.
In summary, the major objective of my research is to develop latent class methods and explore the hidden structure within the transportation data, and the approaches I employed can also be implemented for similar research questions in other areas.
Advisors/Committee Members: Guo, Feng (committeechair), Kim, Inyoung (committee member), Deng, Xinwei (committee member), Rakha, Hesham A. (committee member).
Subjects/Keywords: Transportation; Mixture model; Quantile regression
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APA (6th Edition):
Zhang, D. (2015). Latent Class Model in Transportation Study. (Doctoral Dissertation). Virginia Tech. Retrieved from http://hdl.handle.net/10919/51203
Chicago Manual of Style (16th Edition):
Zhang, Dengfeng. “Latent Class Model in Transportation Study.” 2015. Doctoral Dissertation, Virginia Tech. Accessed February 28, 2021.
http://hdl.handle.net/10919/51203.
MLA Handbook (7th Edition):
Zhang, Dengfeng. “Latent Class Model in Transportation Study.” 2015. Web. 28 Feb 2021.
Vancouver:
Zhang D. Latent Class Model in Transportation Study. [Internet] [Doctoral dissertation]. Virginia Tech; 2015. [cited 2021 Feb 28].
Available from: http://hdl.handle.net/10919/51203.
Council of Science Editors:
Zhang D. Latent Class Model in Transportation Study. [Doctoral Dissertation]. Virginia Tech; 2015. Available from: http://hdl.handle.net/10919/51203
Virginia Tech
10.
Islam, Md Rauful.
A Study on Use of Wide-Area Persistent Video Data for Modeling Traffic Characteristics.
Degree: MS, Civil Engineering, 2019, Virginia Tech
URL: http://hdl.handle.net/10919/99464
► This study explores the potential of vehicle trajectory data obtained from Wide Area Motion Imagery for modeling and analyzing traffic characteristics. The data in question…
(more)
▼ This study explores the potential of vehicle trajectory data obtained from Wide Area Motion Imagery for modeling and analyzing traffic characteristics. The data in question is collected by PV Labs and also known as persistent wide-area video. This video, in combination with PVLab's integrated Tactical Content Management System's spatiotemporal capability, automatically identifies and captures every vehicle in the video view frame, storing each vehicle with a discrete ID, track ID, and time-stamped location. This unique data capture provides comprehensive vehicle trajectory information. This thesis explores the use of data collected by the PVLab's system for an approximate area of 4 square kilometers area in the CBD area of Hamilton, Canada for use in understanding traffic characteristics. The data was collected for two three-hour continuous periods, one in the morning and one in the evening of the same day. Like any other computer vision algorithm, this data suffers from false detection, no detection, and other inaccuracies caused by faulty image registration. Data filtering requirements to remove noisy trajectories and reduce error is developed and presented. A methodology for extracting microscopic traffic data (gap, relative velocity, acceleration, speed) from the vehicle trajectories is presented in details.
This study includes the development of a data model for storing this type of large-scale spatiotemporal data. The proposed data model is a combination of two efficient trajectory data storing techniques, the 3-D schema and the network schema and was developed to store trajectory information along with associated microscopic traffic information. The data model is designed to run fast queries on trajectory information. A 15-minute sample of tracks was validated using manual extraction from imagery frames from the video. Microscopic traffic data is extracted from this trajectory data using customized GIS analysis. Resulting tracks were map-matched to roads and individual lanes to support macro and microscopic traffic characteristic extraction. The final processed dataset includes vehicles and their trajectories for an area of approximately 4-square miles that includes a dense and complex urban network of roads over two continuous three-hour periods.
Two subsets of the data were extracted, cleaned, and processed for use in calibrating car-following sub-models used in microscopic simulations. The car-following model is one of the cornerstones of any simulation based traffic analysis. Calibrating and validating these models is essential for enhancing the ability of the model's capability of representing local traffic. Calibration efforts have previously been limited by the availability and accuracy of microscopic traffic data. Even datasets like the NGSIM data are restricted in either time or space. Trajectory data of all vehicles over a wide area during an extended period of time can provide new insight into microscopic models. Persistent wide-area imagery provides a source for this data. This study explores…
Advisors/Committee Members: Hancock, Kathleen L. (committeechair), Rakha, Hesham A. (committee member), Murray-Tuite, Pamela Marie (committee member).
Subjects/Keywords: Traffic Data; Transport Geographic; Wide-area Motion Imagery; Vehicle Trajectory; Car-Following Model Calibration
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APA (6th Edition):
Islam, M. R. (2019). A Study on Use of Wide-Area Persistent Video Data for Modeling Traffic Characteristics. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/99464
Chicago Manual of Style (16th Edition):
Islam, Md Rauful. “A Study on Use of Wide-Area Persistent Video Data for Modeling Traffic Characteristics.” 2019. Masters Thesis, Virginia Tech. Accessed February 28, 2021.
http://hdl.handle.net/10919/99464.
MLA Handbook (7th Edition):
Islam, Md Rauful. “A Study on Use of Wide-Area Persistent Video Data for Modeling Traffic Characteristics.” 2019. Web. 28 Feb 2021.
Vancouver:
Islam MR. A Study on Use of Wide-Area Persistent Video Data for Modeling Traffic Characteristics. [Internet] [Masters thesis]. Virginia Tech; 2019. [cited 2021 Feb 28].
Available from: http://hdl.handle.net/10919/99464.
Council of Science Editors:
Islam MR. A Study on Use of Wide-Area Persistent Video Data for Modeling Traffic Characteristics. [Masters Thesis]. Virginia Tech; 2019. Available from: http://hdl.handle.net/10919/99464
Virginia Tech
11.
Hajameeran, Alima Jafreen.
A System-wide Planning Tool to Evaluate Access from Crash Sites to Medical Facilities in Virginia.
Degree: MS, Civil Engineering, 2019, Virginia Tech
URL: http://hdl.handle.net/10919/88881
► An objective of emergency responders is to safely transport crash victims from crash sites to medical facilities. Ensuring adequate access is an important goal of…
(more)
▼ An objective of emergency responders is to safely transport crash victims from crash sites to medical facilities. Ensuring adequate access is an important goal of highway safety professionals. This study proposes a proof of concept for a planning tool that evaluates this access in the Commonwealth of
Virginia. This study focuses on serious injury crash sites because the number of serious injuries and serious injury rate are now included as reportable safety performance measures for state highway safety agencies. Travel times from serious injury crash sites to medical facilities are used to identify areas that do not have timely access. Risk and mitigation assessments are performed by dividing the study area into equal sized cells. Risk and mitigation assessments are based on number of crashes and response travel times to the closest medical facility, respectively. These assessments are used to generate a proof of concept for a crash response planning tool which enables planners to identify areas that do not have timely access from crash sites to medical facilities.
Advisors/Committee Members: Hancock, Kathleen L. (committeechair), Katz, Bryan J. (committee member), Rakha, Hesham A. (committee member).
Subjects/Keywords: Crash Response Planning Tool; Medical Facility Coverage
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APA (6th Edition):
Hajameeran, A. J. (2019). A System-wide Planning Tool to Evaluate Access from Crash Sites to Medical Facilities in Virginia. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/88881
Chicago Manual of Style (16th Edition):
Hajameeran, Alima Jafreen. “A System-wide Planning Tool to Evaluate Access from Crash Sites to Medical Facilities in Virginia.” 2019. Masters Thesis, Virginia Tech. Accessed February 28, 2021.
http://hdl.handle.net/10919/88881.
MLA Handbook (7th Edition):
Hajameeran, Alima Jafreen. “A System-wide Planning Tool to Evaluate Access from Crash Sites to Medical Facilities in Virginia.” 2019. Web. 28 Feb 2021.
Vancouver:
Hajameeran AJ. A System-wide Planning Tool to Evaluate Access from Crash Sites to Medical Facilities in Virginia. [Internet] [Masters thesis]. Virginia Tech; 2019. [cited 2021 Feb 28].
Available from: http://hdl.handle.net/10919/88881.
Council of Science Editors:
Hajameeran AJ. A System-wide Planning Tool to Evaluate Access from Crash Sites to Medical Facilities in Virginia. [Masters Thesis]. Virginia Tech; 2019. Available from: http://hdl.handle.net/10919/88881
Virginia Tech
12.
Fedor, Craig Steven.
Synthesizing Vehicle Cornering Modes for Energy Consumption Analysis.
Degree: MS, Mechanical Engineering, 2018, Virginia Tech
URL: http://hdl.handle.net/10919/83556
► Automotive vehicle manufacturers have been facing increased pressures from legislative bodies and consumers to reduce the fuel consumption and harmful emissions of their newly produced…
(more)
▼ Automotive vehicle manufacturers have been facing increased pressures from legislative bodies and consumers to reduce the fuel consumption and harmful emissions of their newly produced vehicles as a result of new research showing the detrimental effects these emissions have on the environment. These pressures are encouraging manufactures and researchers to invest billions of dollars into the development of new advanced vehicle technologies. Some of these investments have resulted in substantial progress in powertrain technologies that have led to the preliminary adoption of electrified powertrain vehicles. Other areas of research are actively working to reduce the energy consumption of a vehicle, regardless of its powertrain, by influencing driver behavior and by optimizing the way a vehicle travels between an origin and destination. This intelligent vehicle routing is done by analyzing a range of possible routes and selecting the route that consumes the least amount of fuel.
An accurate method for predetermining vehicle energy expenditure along a given route before it is driven is needed to effectively implement intelligent vehicle routing systems. One common method is the generation of a road network-wide database with energy use figures for each section of road. This method requires expensive experimentation trials or network simulation software. Individual-level vehicle predictive energy estimation eliminates the need for costly fuel use generation by utilizing vehicle velocity generation techniques and vehicle powertrain models. Estimation of individual vehicle energy consumption along a route is done by identifying an origin-destination pair, detecting required full-stops along the path, and synthesizing multiple stop-to-stop velocity modes between each set of stops. The resulting velocity profile is paired with a specific vehicle powertrain model to determine fuel consumption. A drawback of this route generation technique is that the vehicle path is assumed to be one-dimensional and lacks inclusion of road curves and their associated velocity changes to maintain passenger comfort.
This thesis evaluates the merit of discounting road curves in predictive vehicle energy consumption analyses and presents a technique for modeling common road corners that require velocity changes to limit passenger discomfort. The resulting corner synthesis method is combined with a validated vehicle powertrain model to complete full route consumption modeling. Two routes, an urban and highway, are modeled and driven to evaluate the accuracy of the full simulation model when compared with on-road data. The results show that corners can largely be ignored during energy consumption analysis for highways. The cornering effects on a vehicle during urban driving, however, should be included in urban route analyses with multiple road curves. Inclusion of the cornering effects during an example urban route analysis decreased the error between the on-road consumption data and the simulation results.
Advisors/Committee Members: Nelson, Douglas J. (committeechair), Rakha, Hesham A. (committee member), Leonessa, Alexander (committee member).
Subjects/Keywords: battery electric vehicle; cornering; road curves; energy consumption; lateral acceleration; eco-routing
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APA (6th Edition):
Fedor, C. S. (2018). Synthesizing Vehicle Cornering Modes for Energy Consumption Analysis. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/83556
Chicago Manual of Style (16th Edition):
Fedor, Craig Steven. “Synthesizing Vehicle Cornering Modes for Energy Consumption Analysis.” 2018. Masters Thesis, Virginia Tech. Accessed February 28, 2021.
http://hdl.handle.net/10919/83556.
MLA Handbook (7th Edition):
Fedor, Craig Steven. “Synthesizing Vehicle Cornering Modes for Energy Consumption Analysis.” 2018. Web. 28 Feb 2021.
Vancouver:
Fedor CS. Synthesizing Vehicle Cornering Modes for Energy Consumption Analysis. [Internet] [Masters thesis]. Virginia Tech; 2018. [cited 2021 Feb 28].
Available from: http://hdl.handle.net/10919/83556.
Council of Science Editors:
Fedor CS. Synthesizing Vehicle Cornering Modes for Energy Consumption Analysis. [Masters Thesis]. Virginia Tech; 2018. Available from: http://hdl.handle.net/10919/83556
Virginia Tech
13.
Bryant, Craig William.
Study of Truck Driver Behavior at Onset of Yellow Traffic Signal Indication for the Design of Yellow Times.
Degree: MS, Civil Engineering, 2014, Virginia Tech
URL: http://hdl.handle.net/10919/25149
► Traffic signal violations by drivers are a leading contributor to crashes at signalized intersections. The yellow indication is used to inform drivers of an upcoming…
(more)
▼ Traffic signal violations by drivers are a leading
contributor to crashes at signalized intersections. The yellow indication is used to inform drivers of an upcoming change in the status of the traffic signal. Yellow-interval durations are currently calculated to provide dilemma zone protection for passenger cars. Due to differences in vehicle characteristics and driver characteristics, heavy trucks such as tractor-trailers behave differently at the onset of a yellow-indication. The research presented in this thesis characterizes the difference in driver behavior between truck and light-duty vehicle driver behavior at the onset of yellow-indication and then revises the yellow timing procedures to address the truck requirements.
A dataset of 910 stop-go records was collected using a truck driving simulator located at the
Virginia Tech Transportation Institute (VTTI). Participant drivers were placed in a simulated urban environment with a speed limit of 45 MPH and instructed to drive as they would regularly drive in such a situation. Participant drivers were recruited using the VTTI participant database.
Using the data collected as part of this research effort, statistical models were created to model driver perception-reaction times (PRTs) and deceleration levels considering driver attributes (age) and the time to the intersection at the onset of yellow. The data collected, along with the statistical models developed were compared to data collected and statistical models created by the same research organization in 2008 in a similar study of passenger car driver behavior. Lastly, a Monte-Carlo simulation was conducted to develop appropriate yellow indication timings to provide adequate dilemma zone protection for trucks.
Advisors/Committee Members: Rakha, Hesham A. (committeechair), Elshawarby, Ihab E. (committee member), Katz, Bryan J. (committee member).
Subjects/Keywords: Trucks; Yellow Signal; Design of Yellow Times
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APA (6th Edition):
Bryant, C. W. (2014). Study of Truck Driver Behavior at Onset of Yellow Traffic Signal Indication for the Design of Yellow Times. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/25149
Chicago Manual of Style (16th Edition):
Bryant, Craig William. “Study of Truck Driver Behavior at Onset of Yellow Traffic Signal Indication for the Design of Yellow Times.” 2014. Masters Thesis, Virginia Tech. Accessed February 28, 2021.
http://hdl.handle.net/10919/25149.
MLA Handbook (7th Edition):
Bryant, Craig William. “Study of Truck Driver Behavior at Onset of Yellow Traffic Signal Indication for the Design of Yellow Times.” 2014. Web. 28 Feb 2021.
Vancouver:
Bryant CW. Study of Truck Driver Behavior at Onset of Yellow Traffic Signal Indication for the Design of Yellow Times. [Internet] [Masters thesis]. Virginia Tech; 2014. [cited 2021 Feb 28].
Available from: http://hdl.handle.net/10919/25149.
Council of Science Editors:
Bryant CW. Study of Truck Driver Behavior at Onset of Yellow Traffic Signal Indication for the Design of Yellow Times. [Masters Thesis]. Virginia Tech; 2014. Available from: http://hdl.handle.net/10919/25149
Virginia Tech
14.
Almannaa, Mohammed Hamad.
Field Evaluation of the Eco-Cooperative Adaptive Cruise Control in the Vicinity of Signalized Intersections.
Degree: MS, Civil Engineering, 2016, Virginia Tech
URL: http://hdl.handle.net/10919/81857
► Traffic signals are used at intersections to manage the flow of vehicles by allocating right-of-way in a timely manner for different users of the intersection.…
(more)
▼ Traffic signals are used at intersections to manage the flow of vehicles by allocating right-of-way in a timely manner for different users of the intersection. Traffic signals are therefore installed at an intersection to improve overall safety and to decrease vehicular average delay. However, the variation of driving speed in response to these signals causes an increase in fuel consumption and air emission levels. One solution to this problem is Eco-Cooperative Adaptive Cruise Control (Eco-CACC), which attempts to reduce vehicle fuel consumption and emission levels by optimizing driver behavior in the vicinity of a signalized intersection. Various Eco-CACC algorithms have been proposed by researchers to address this issue. With the help of vehicle-to-infrastructure (V2I) and vehicle-to-vehicle (V2V) communication, algorithms are being developed that utilize signal phasing and timing (SPaT) data together with queue information to optimize vehicle trajectories in the vicinity of signalized intersections.
The research presented in this thesis constitutes the third phase of a project that entailed developing and evaluating an Eco-CACC system. Its main objective is to evaluate the benefits of the newly developed Eco-CACC algorithm that was proposed by the Center for Sustainable Mobility at the
Virginia Tech Transportation Institute. This algorithm uses advanced signal information (SPaT) to compute the fuel-optimal trajectory of vehicles, and, then, send recommended speeds to drivers as an audio message or implement them directly into the subject vehicle. The objective of this study is to quantitatively quantify the fuel-efficiency of the Eco-CACC system in a real field environment. In addition, another goal of this study is to address the implementation issues and challenges with the field application of the Eco-CACC system.
A dataset of 2112 trips were collected as part of this research effort using a 2014 Cadillac SRX equipped with a vehicle onboard unit for (V2V) and (V2I) communication. A total of 32 participants between the ages of 18 and 30 were randomly selected from one age group (18-30) with an equal number of males and females. The controlled experiment was conducted on the
Virginia Smart Road facility during daylight hours for dry pavement conditions. The controlled field experiment included four different scenarios: normal driving, driving with red indication countdown information provided to drivers, driving with recommended speed information computed by the Eco-CACC system and delivered to drivers, and finally automated driving (automated Eco-CACC system). The controlled field experiment was conducted for four values of red indication offsets along an uphill and downhill approach.
The collected data were compared with regard to fuel economy and travel time over a fixed distance upstream and downstream of the intersection (820 ft (250 m) upstream of the intersection to 590 ft (180 m) downstream for a total length of 1410 ft (430 m)). The results demonstrate that the Eco-CACC system is very…
Advisors/Committee Members: Rakha, Hesham A. (committeechair), Loulizi, Amara (committee member), Elshawarby, Ihab E. (committee member).
Subjects/Keywords: Eco-driving; Signal Timing; Fuel Consumption; Eco-Cooperative Adaptive Cruise Control; Autonomous Vehicles; Automated Vehicles; Signalized Intersections
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APA ·
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APA (6th Edition):
Almannaa, M. H. (2016). Field Evaluation of the Eco-Cooperative Adaptive Cruise Control in the Vicinity of Signalized Intersections. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/81857
Chicago Manual of Style (16th Edition):
Almannaa, Mohammed Hamad. “Field Evaluation of the Eco-Cooperative Adaptive Cruise Control in the Vicinity of Signalized Intersections.” 2016. Masters Thesis, Virginia Tech. Accessed February 28, 2021.
http://hdl.handle.net/10919/81857.
MLA Handbook (7th Edition):
Almannaa, Mohammed Hamad. “Field Evaluation of the Eco-Cooperative Adaptive Cruise Control in the Vicinity of Signalized Intersections.” 2016. Web. 28 Feb 2021.
Vancouver:
Almannaa MH. Field Evaluation of the Eco-Cooperative Adaptive Cruise Control in the Vicinity of Signalized Intersections. [Internet] [Masters thesis]. Virginia Tech; 2016. [cited 2021 Feb 28].
Available from: http://hdl.handle.net/10919/81857.
Council of Science Editors:
Almannaa MH. Field Evaluation of the Eco-Cooperative Adaptive Cruise Control in the Vicinity of Signalized Intersections. [Masters Thesis]. Virginia Tech; 2016. Available from: http://hdl.handle.net/10919/81857
Virginia Tech
15.
Tu, Ran.
Network-wide Assessment of Eco-Cooperative Adaptive Cruise Control Systems on Freeway and Arterial Facilities.
Degree: MS, Civil Engineering, 2016, Virginia Tech
URL: http://hdl.handle.net/10919/71385
► The environmental impact of a transportation system is critical in the assessment of the transportation system performance. Eco-Cooperative Adaptive Cruise Control (Eco-CACC) systems attempt to…
(more)
▼ The environmental impact of a transportation system is critical in the assessment of the transportation system performance. Eco-Cooperative Adaptive Cruise Control (Eco-CACC) systems attempt to minimize vehicle fuel consumption and emission levels by controlling vehicle speed and acceleration levels. The majority of previous research efforts developed and applied Eco-CACC systems on either freeway or signalized intersections independently on simple and small transportation networks without consideration of the interaction among these controls.
This thesis extends the state-of-the-art in Eco-CACC evaluation by conducting a comprehensive evaluation on a complex network considering Eco-CACC control on both freeways and arterials individually and simultaneously. The goal of this study is to compare Eco-CACCs on arterial facilities (Eco-CACC-A), freeway facilities (Eco-CACC-F) and both facilities (Eco-CACC-F+A). The effects of Eco-CACC are evaluated considering various Measures of Effectiveness (MOEs), including: average vehicle delay, fuel consumption, and emission levels using simulated results from INTEGRATION, a microscopic traffic assignment and simulation software, considering different freeway speed limits, traffic demand levels and system market penetration rates. In total, 19 traffic scenarios for each of the four different cases (Eco-CACC-A, Eco-CACC-F and Eco-CACC-F+A plus a base no control case) were tested. In total 760 simulation runs were conducted (4 cases * 19 scenarios * 10 repetitions). T-tests and pairwise mean comparison (Tukey HSD) were conducted to identify any statistical differences between control cases and the base case from the simulation results. This thesis shows that arterial and freeway Eco-CACCs can work well together and their effects will be largely influenced by network characteristics.
Advisors/Committee Members: Rakha, Hesham A. (committeechair), Du, Jianhe (committee member), Yang, Hao (committee member).
Subjects/Keywords: Simulation; Fuel consumption and emission model; Eco-CACC; Connected vehicle
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APA (6th Edition):
Tu, R. (2016). Network-wide Assessment of Eco-Cooperative Adaptive Cruise Control Systems on Freeway and Arterial Facilities. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/71385
Chicago Manual of Style (16th Edition):
Tu, Ran. “Network-wide Assessment of Eco-Cooperative Adaptive Cruise Control Systems on Freeway and Arterial Facilities.” 2016. Masters Thesis, Virginia Tech. Accessed February 28, 2021.
http://hdl.handle.net/10919/71385.
MLA Handbook (7th Edition):
Tu, Ran. “Network-wide Assessment of Eco-Cooperative Adaptive Cruise Control Systems on Freeway and Arterial Facilities.” 2016. Web. 28 Feb 2021.
Vancouver:
Tu R. Network-wide Assessment of Eco-Cooperative Adaptive Cruise Control Systems on Freeway and Arterial Facilities. [Internet] [Masters thesis]. Virginia Tech; 2016. [cited 2021 Feb 28].
Available from: http://hdl.handle.net/10919/71385.
Council of Science Editors:
Tu R. Network-wide Assessment of Eco-Cooperative Adaptive Cruise Control Systems on Freeway and Arterial Facilities. [Masters Thesis]. Virginia Tech; 2016. Available from: http://hdl.handle.net/10919/71385
Virginia Tech
16.
Ong, Boon Teck.
Study of Bus Driver Behavior at the Onset of Yellow Traffic Signal Indication for the Design of Yellow Time Durations.
Degree: MS, Civil Engineering, 2014, Virginia Tech
URL: http://hdl.handle.net/10919/64454
► Driver violations at traffic signals are a major cause of intersection vehicle crashes. The yellow interval is used to inform approaching drivers of an upcoming…
(more)
▼ Driver violations at traffic signals are a major cause of intersection vehicle crashes. The yellow interval is used to inform approaching drivers of an upcoming change in the traffic signal indication from green to red. Current yellow-interval durations are currently calculated to accommodate for dilemma zone protection for passenger cars only. Buses with different vehicle, driver, and occupancy characteristics behave differently at the onset of a yellow indication. The research presented in this thesis characterizes the difference between bus and passenger car driver behavior at the onset of yellow-indication. A revised set of yellow timing procedures are presented to address the requirements for bus dilemma zone protection.
A dataset of 864 stop-go records were collected as part of the research effort using a school bus approaching a traffic signal on the
Virginia Smart Road facility. The experiment was conducted at an instructed speed limit of 57 km/h (35 mph) approach speed where participant drivers were presented with yellow indications. A total of 36 participating bus drivers were randomly selected from three age groups (under 40 years old, 40 to 64 years old and 65 and above) with equal number of male and female for each age group.
Using the data collected as part of this research effort, statistical models were created to model bus driver perception-reaction times (PRTs) and deceleration levels considering driver attributes (age and gender), roadway grade, vehicle approach speed, and time to intersection (TTI) at the onset of the yellow indication. A Monte-Carlo simulation was conducted to develop appropriate yellow indication timings to provide adequate dilemma zone protection for buses. Lookup tables were then developed for different reliability levels to provide practical guidelines for the design of yellow signal timings to accommodate different bus percentages within the traffic stream. The recommended change durations can be integrated within the Vehicle Infrastructure Integration (VII) initiative to provide customizable driver warnings prior to a transition to a red indication.
Advisors/Committee Members: Rakha, Hesham A. (committeechair), Elshawarby, Ihab E. (committee member), Katz, Bryan J. (committee member).
Subjects/Keywords: Yellow Interval; Signal Timing; Dilemma Zone; PRT; Vehicle Deceleration; Bus
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APA (6th Edition):
Ong, B. T. (2014). Study of Bus Driver Behavior at the Onset of Yellow Traffic Signal Indication for the Design of Yellow Time Durations. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/64454
Chicago Manual of Style (16th Edition):
Ong, Boon Teck. “Study of Bus Driver Behavior at the Onset of Yellow Traffic Signal Indication for the Design of Yellow Time Durations.” 2014. Masters Thesis, Virginia Tech. Accessed February 28, 2021.
http://hdl.handle.net/10919/64454.
MLA Handbook (7th Edition):
Ong, Boon Teck. “Study of Bus Driver Behavior at the Onset of Yellow Traffic Signal Indication for the Design of Yellow Time Durations.” 2014. Web. 28 Feb 2021.
Vancouver:
Ong BT. Study of Bus Driver Behavior at the Onset of Yellow Traffic Signal Indication for the Design of Yellow Time Durations. [Internet] [Masters thesis]. Virginia Tech; 2014. [cited 2021 Feb 28].
Available from: http://hdl.handle.net/10919/64454.
Council of Science Editors:
Ong BT. Study of Bus Driver Behavior at the Onset of Yellow Traffic Signal Indication for the Design of Yellow Time Durations. [Masters Thesis]. Virginia Tech; 2014. Available from: http://hdl.handle.net/10919/64454
Virginia Tech
17.
Ala, Mani Venkat Sai Kumar.
Eco-Cooperative Adaptive Cruise Control at Signalized Intersections Considering Vehicle Queues.
Degree: MS, Civil Engineering, 2016, Virginia Tech
URL: http://hdl.handle.net/10919/78884
► Traffic signals typically produce vehicle stops and thus increase vehicle fuel consumption levels. Vehicle stops produced by traffic signals, decrease vehicle fuel economy on arterial…
(more)
▼ Traffic signals typically produce vehicle stops and thus increase vehicle fuel consumption levels. Vehicle stops produced by traffic signals, decrease vehicle fuel economy on arterial roads making it significantly lower than that on freeways. Eco-Cooperative Adaptive Cruise Control (Eco-CACC) systems can improve vehicle fuel efficiency by receiving Signal Phasing and Timing (SPaT) data form downstream signalized intersections via vehicle-to-infrastructure communication. The algorithm that was developed in an earlier study provides advisory speed recommendations to drivers to reduce vehicle fuel consumption levels in the vicinity of traffic signalized intersections. The research presented in this thesis enhances the algorithm by adding a queue length estimation component and incorporates the algorithm in the INTEGRATION microscopic traffic simulation software to test the system under varying conditions. The enhanced Eco-CACC algorithm is then tested in a simulation environment considering different levels of connected vehicle (CV) market penetration levels. The simulation analysis demonstrates that the algorithm is able to reduce the vehicle fuel consumption level by as high as 40%. Moreover, the overall benefits of the proposed algorithm is evaluated for different intersection configurations and CV market penetration rates (MPRs). The results demonstrate that for single lane approaches, the algorithm can reduce the overall fuel consumption levels and that higher MPRs result in larger savings. While for multilane approaches, lower MPRs produce negative impacts on fuel efficiency; only when MPRs are greater than 30%, can the algorithm work effectively in reducing fuel consumption levels. Subsequently a sensitivity analysis is conducted. The sensitivity analysis demonstrates that higher market penetration rates of Eco-CACC enabled vehicles can improve the environmental benefits of the algorithm, and the overall savings in fuel consumption are as high as 19% when all vehicles are equipped with the system. While, on multi-lane approaches, the algorithm has negative impacts on fuel consumption levels when the market penetration rate is lower than 30 percent. The analysis also indicates that the length of control segments, the SPaT plan, and the traffic demand levels affect the algorithm performance significantly. The study further demonstrates that the algorithm has negative impacts on fuel consumption levels when the network is over-saturated.
Advisors/Committee Members: Rakha, Hesham A. (committeechair), Yang, Hao (committee member), Hancock, Kathleen L. (committee member).
Subjects/Keywords: Eco-Cooperative driving; Cooperative Adaptive Cruise Control; Connected Vehicles; Traffic Signals; Eco-transportation systems
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APA ·
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APA (6th Edition):
Ala, M. V. S. K. (2016). Eco-Cooperative Adaptive Cruise Control at Signalized Intersections Considering Vehicle Queues. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/78884
Chicago Manual of Style (16th Edition):
Ala, Mani Venkat Sai Kumar. “Eco-Cooperative Adaptive Cruise Control at Signalized Intersections Considering Vehicle Queues.” 2016. Masters Thesis, Virginia Tech. Accessed February 28, 2021.
http://hdl.handle.net/10919/78884.
MLA Handbook (7th Edition):
Ala, Mani Venkat Sai Kumar. “Eco-Cooperative Adaptive Cruise Control at Signalized Intersections Considering Vehicle Queues.” 2016. Web. 28 Feb 2021.
Vancouver:
Ala MVSK. Eco-Cooperative Adaptive Cruise Control at Signalized Intersections Considering Vehicle Queues. [Internet] [Masters thesis]. Virginia Tech; 2016. [cited 2021 Feb 28].
Available from: http://hdl.handle.net/10919/78884.
Council of Science Editors:
Ala MVSK. Eco-Cooperative Adaptive Cruise Control at Signalized Intersections Considering Vehicle Queues. [Masters Thesis]. Virginia Tech; 2016. Available from: http://hdl.handle.net/10919/78884
18.
Fadhloun, Karim.
Modeling Human And Machine-In-The-Loop In Car-Following Theory.
Degree: PhD, Civil Engineering, 2019, Virginia Tech
URL: http://hdl.handle.net/10919/95208
► Even though the study of the longitudinal motion of vehicles spanned over several decades leading to the development of more precise and complex car-following models,…
(more)
▼ Even though the study of the longitudinal motion of vehicles spanned over several decades leading to the development of more precise and complex car-following models, an important aspect was constantly overlooked in those models. In fact, due to the complexity of modeling the human-in-the-loop, the vehicle and the driver were almost always assumed to represent a single entity. More specifically, ignoring driver behavior and integrating it to the vehicle allowed avoiding to deal with the challenges related to modeling human behavior. The difficulty of mathematically modeling the vehicle and the driver as two independent components rather than one unique system is due to two main reasons. First, there are numerous car models and types that make it difficult to determine the different parameters impacting the performance of the vehicle as they differ from vehicle to vehicle. Second, different driving patterns exist and the fact that they are mostly dependent on human behavior and psychology makes them very difficult to replicate mathematically. The research presented in this thesis provides a comprehensive investigation of the human-in-the-loop component in car-following theory leading to a better understanding of the human-vehicle interaction. This study was initiated due to the noticeable overlooking of driver behavior in the existing literature which, as a result, fails to capture the effect of human control and perception errors.
Advisors/Committee Members: Rakha, Hesham A. (committeechair), Hancock, Kathleen L. (committee member), Elshawarby, Ihab E. (committee member), Loulizi, Amara (committee member).
Subjects/Keywords: Human Behavior; Car Following Theory; Platooning; Driving Pattern; Human-In-The-Loop
…VIRGINIA TECH COMPREHENSIVE POWER-BASED FUEL CONSUMPTION MODEL ____ 116
7.4
COLLECTED… …naturalistic data of the 100Car study that was gathered by the Virginia Tech Transportation Institute…
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APA (6th Edition):
Fadhloun, K. (2019). Modeling Human And Machine-In-The-Loop In Car-Following Theory. (Doctoral Dissertation). Virginia Tech. Retrieved from http://hdl.handle.net/10919/95208
Chicago Manual of Style (16th Edition):
Fadhloun, Karim. “Modeling Human And Machine-In-The-Loop In Car-Following Theory.” 2019. Doctoral Dissertation, Virginia Tech. Accessed February 28, 2021.
http://hdl.handle.net/10919/95208.
MLA Handbook (7th Edition):
Fadhloun, Karim. “Modeling Human And Machine-In-The-Loop In Car-Following Theory.” 2019. Web. 28 Feb 2021.
Vancouver:
Fadhloun K. Modeling Human And Machine-In-The-Loop In Car-Following Theory. [Internet] [Doctoral dissertation]. Virginia Tech; 2019. [cited 2021 Feb 28].
Available from: http://hdl.handle.net/10919/95208.
Council of Science Editors:
Fadhloun K. Modeling Human And Machine-In-The-Loop In Car-Following Theory. [Doctoral Dissertation]. Virginia Tech; 2019. Available from: http://hdl.handle.net/10919/95208
19.
Sangster, John.
Operational Analysis of Alternative Intersections.
Degree: PhD, Civil Engineering, 2015, Virginia Tech
URL: http://hdl.handle.net/10919/75221
► Alternative intersections and interchanges, such as the diverging diamond interchange (DDI), the restricted crossing u-turn (RCUT), and the displaced left-turn intersection (DLT), have the potential…
(more)
▼ Alternative intersections and interchanges, such as the diverging diamond interchange (DDI), the restricted crossing u-turn (RCUT), and the displaced left-turn intersection (DLT), have the potential to both improve safety and reduce delay. However, partially due to lingering questions about analysis methods and service measures for these designs, their rate of implementation remains low. This research attempts to answer three key questions. Can alternative intersections and interchanges be incorporated into the existing level of service and service measure schema, or is a new service measure with an updated level of service model required? Is the behavior of drivers at alternative intersections fundamentally similar to those at conventional intersections, such that traffic microsimulation applications can accurately model the behaviors observed in the field? Finally, is the planning level tool made available through FHWA an accurate predictor of the relative performance of various alternatives, or is an updated tool necessary?
Discussion and case study analysis are used to explore the existing level of service and service measure schema. The existing control delay measure is recommended to be replaced with a proposed junction delay measure that incorporates geometric delay, with the existing level of service schema based on control type recommended to be replaced by a proposed schema using demand volume. A case study validation of micro- and macroscopic analysis methods is conducted, finding the two microscopic methods investigated to match field observed vehicle delays within 3 to 7 seconds for all designs tested, and macroscopic HCM method matching within 3 seconds for the DDI, 35 seconds for the RCUT, and 130 seconds for the DLT design. Taking the critical lane analysis method to be a valid measure of operations, the demand-volume limitations of each alternative design is explored using eighteen geometric configurations and approximately three thousand volume scenarios, with the DLT design predicted to accommodate the highest demand volumes before failure is reached. Finally, six geometries are examined using both the planning-level tool and the validated microsimulation tool, finding that the curve of the capacity-to-delay relationship varies for each alternative design, invalidating the use of critical lane analysis as a comparative tool.
Advisors/Committee Members: Rakha, Hesham A. (committeechair), Hancock, Kathleen L. (committee member), Du, Jianhe (committee member), Katz, Bryan J. (committee member).
Subjects/Keywords: traffic operations; microsimulation; alternative intersections; capacity; delay
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APA (6th Edition):
Sangster, J. (2015). Operational Analysis of Alternative Intersections. (Doctoral Dissertation). Virginia Tech. Retrieved from http://hdl.handle.net/10919/75221
Chicago Manual of Style (16th Edition):
Sangster, John. “Operational Analysis of Alternative Intersections.” 2015. Doctoral Dissertation, Virginia Tech. Accessed February 28, 2021.
http://hdl.handle.net/10919/75221.
MLA Handbook (7th Edition):
Sangster, John. “Operational Analysis of Alternative Intersections.” 2015. Web. 28 Feb 2021.
Vancouver:
Sangster J. Operational Analysis of Alternative Intersections. [Internet] [Doctoral dissertation]. Virginia Tech; 2015. [cited 2021 Feb 28].
Available from: http://hdl.handle.net/10919/75221.
Council of Science Editors:
Sangster J. Operational Analysis of Alternative Intersections. [Doctoral Dissertation]. Virginia Tech; 2015. Available from: http://hdl.handle.net/10919/75221
20.
Kastenhofer, Ilona Ottilia.
Multimodal Assessment of Recurrent and Non-recurrent Conditions on Urban Streets.
Degree: PhD, Civil Engineering, 2014, Virginia Tech
URL: http://hdl.handle.net/10919/64908
► The methodology to measure the performance of urban streets was significantly revised in the latest edition of the Highway Capacity Manual (HCM 2010). Urban Streets,…
(more)
▼ The methodology to measure the performance of urban streets was significantly revised in the latest edition of the Highway Capacity Manual (HCM 2010). Urban Streets, which include urban and suburban signalized arterial highways, typically serve the four modes of transportation (auto, transit, pedestrian and bicycle) and are frequently congested. Analyzing both recurrent and non-recurrent conditions is essential. In this dissertation, the author addressed several urban streets related issues by developing an alternative method to measure recurrent multimodal conditions on urban streets; gathering feedback relating to the key elements of the developed method; and developing a probabilistic method to analyze and measure non-recurrent conditions. Real life sample applications were performed for both developed methods. The developed multimodal method addresses the following: (1) the use of level of service (LOS) step functions; (2) the comparability of LOS results across modes; (3) the impacts of modes on other modes; (4) the establishment of thresholds; (5) accuracy; and (6) user perceptions in measuring multimodal conditions on urban streets. Feedback gathered from transportation professionals through focus group meetings and surveys supported most of the features of the developed multimodal method
and provided default values for method application. They were divided on the naming of condition levels and on the number of condition levels to use. Non-recurrent conditions were addressed through the development of a Markovian probabilistic method to analyze and measure the resilience of congested, signalized, arterial highways, for which availability of existing analytical tools is limited. The method results provide a plexiform of information about the rate and speed of recovery of the arterial traffic flow.
Advisors/Committee Members: Hobeika, Antoine G. (committeechair), Abbas, Montasir M. (committeechair), O'Leary, Amy A. (committee member), Rakha, Hesham A. (committee member).
Subjects/Keywords: Urban Streets; Multimodal Conditions; Traffic Resilience; Signalized Arterials; Recurrent; Non-recurrent; Transportation Planning; Traffic Engineering.
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APA (6th Edition):
Kastenhofer, I. O. (2014). Multimodal Assessment of Recurrent and Non-recurrent Conditions on Urban Streets. (Doctoral Dissertation). Virginia Tech. Retrieved from http://hdl.handle.net/10919/64908
Chicago Manual of Style (16th Edition):
Kastenhofer, Ilona Ottilia. “Multimodal Assessment of Recurrent and Non-recurrent Conditions on Urban Streets.” 2014. Doctoral Dissertation, Virginia Tech. Accessed February 28, 2021.
http://hdl.handle.net/10919/64908.
MLA Handbook (7th Edition):
Kastenhofer, Ilona Ottilia. “Multimodal Assessment of Recurrent and Non-recurrent Conditions on Urban Streets.” 2014. Web. 28 Feb 2021.
Vancouver:
Kastenhofer IO. Multimodal Assessment of Recurrent and Non-recurrent Conditions on Urban Streets. [Internet] [Doctoral dissertation]. Virginia Tech; 2014. [cited 2021 Feb 28].
Available from: http://hdl.handle.net/10919/64908.
Council of Science Editors:
Kastenhofer IO. Multimodal Assessment of Recurrent and Non-recurrent Conditions on Urban Streets. [Doctoral Dissertation]. Virginia Tech; 2014. Available from: http://hdl.handle.net/10919/64908
Virginia Tech
21.
Abdelghaffar, Hossam Mohamed Abdelwahed.
Developing and Testing a Novel De-centralized Cycle-free Game Theoretic Traffic Signal Controller: A Traffic Efficiency and Environmental Perspective.
Degree: PhD, Electrical Engineering, 2018, Virginia Tech
URL: http://hdl.handle.net/10919/100681
► Traffic congestion negatively affects traveler mobility and air quality. Stop and go vehicular movements associated with traffic jams typically result in higher fuel consumption levels…
(more)
▼ Traffic congestion negatively affects traveler mobility and air quality. Stop and go vehicular movements associated with traffic jams typically result in higher fuel consumption levels compared to cruising at a constant speed. The first objective in the dissertation is to investigate the spatial relationship between air quality and traffic flow patterns. We developed and applied a recursive Bayesian estimation algorithm to estimate the source location (associated with traffic jam) of an airborne contaminant (aerosol) in a simulation environment. This algorithm was compared to the gradient descent algorithm and an extended Kalman filter algorithm. Results suggest that Bayesian estimation is less sensitive to the choice of the initial state and to the plume dispersion model. Consequently, Bayesian estimation was implemented to identify the location (correlated with traffic flows) of the aerosol (soot) that can be attributed to traffic in the vicinity of the Old Dominion University campus, using data collected from a remote sensing system. Results show that the source location of soot pollution is located at congested intersections, which demonstrate that air quality is correlated with traffic flows and congestion caused by signalized intersections.
Sustainable mobility can help reduce traffic congestion and vehicle emissions, and thus, optimizing the performance of available infrastructure via advanced traffic signal controllers has become increasingly appealing. The second objective in the dissertation is to develop a novel de-centralized traffic signal controller, achieved using a Nash bargaining game-theoretic framework, that operates a flexible phasing sequence and free cycle length to adapt to dynamic changes in traffic demand levels. The developed controller was implemented and tested in the INTEGRATION microscopic traffic assignment and simulation software. The proposed controller was compared to the operation of an optimum fixed-time coordinated plan, an actuated controller, a centralized adaptive phase split controller, a decentralized phase split and cycle length controller, and a fully coordinated adaptive phase split, cycle length, and offset optimization controller to evaluate its performance.
Testing was initially conducted on an isolated intersection, showing a 77% reduction in queue length, a 17% reduction in vehicle emission levels, and a 64% reduction in total delay. In addition, the developed controller was tested on an arterial network producing statistically significant reductions in total delay ranging between 36% and 67% and vehicle emissions reductions ranging between 6% and 13%. Analysis of variance, Tukey, and pairwise comparison tests were conducted to establish the significance of the proposed controller. Moreover, the controller was tested on a network of 38 intersections producing significant reduction in the travel time by 23.6%, a reduction in the queue length by 37.6%, and a reduction in CO2 emissions by 10.4%. Finally, the controller was tested on the Los Angeles downtown network…
Advisors/Committee Members: Rakha, Hesham A. (committeechair), Yang, Hao (committee member), Abbott, Amos L (committee member), Woolsey, Craig A. (committee member), Zeng, Haibo (committee member).
Subjects/Keywords: Aerosol detection; source localization; traffic signal controller; game theory
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APA (6th Edition):
Abdelghaffar, H. M. A. (2018). Developing and Testing a Novel De-centralized Cycle-free Game Theoretic Traffic Signal Controller: A Traffic Efficiency and Environmental Perspective. (Doctoral Dissertation). Virginia Tech. Retrieved from http://hdl.handle.net/10919/100681
Chicago Manual of Style (16th Edition):
Abdelghaffar, Hossam Mohamed Abdelwahed. “Developing and Testing a Novel De-centralized Cycle-free Game Theoretic Traffic Signal Controller: A Traffic Efficiency and Environmental Perspective.” 2018. Doctoral Dissertation, Virginia Tech. Accessed February 28, 2021.
http://hdl.handle.net/10919/100681.
MLA Handbook (7th Edition):
Abdelghaffar, Hossam Mohamed Abdelwahed. “Developing and Testing a Novel De-centralized Cycle-free Game Theoretic Traffic Signal Controller: A Traffic Efficiency and Environmental Perspective.” 2018. Web. 28 Feb 2021.
Vancouver:
Abdelghaffar HMA. Developing and Testing a Novel De-centralized Cycle-free Game Theoretic Traffic Signal Controller: A Traffic Efficiency and Environmental Perspective. [Internet] [Doctoral dissertation]. Virginia Tech; 2018. [cited 2021 Feb 28].
Available from: http://hdl.handle.net/10919/100681.
Council of Science Editors:
Abdelghaffar HMA. Developing and Testing a Novel De-centralized Cycle-free Game Theoretic Traffic Signal Controller: A Traffic Efficiency and Environmental Perspective. [Doctoral Dissertation]. Virginia Tech; 2018. Available from: http://hdl.handle.net/10919/100681
Virginia Tech
22.
Ashqar, Huthaifa Issam.
Strategic Design of Smart Bike-Sharing Systems for Smart Cities.
Degree: PhD, Civil Engineering, 2018, Virginia Tech
URL: http://hdl.handle.net/10919/97827
► Traffic congestion has become one of the major challenging problems of modern life in many urban areas. This growing problem leads to negative environmental impacts,…
(more)
▼ Traffic congestion has become one of the major challenging problems of modern life in many urban areas. This growing problem leads to negative environmental impacts, wasted fuel, lost productivity, and increased travel time. In big cities, trains and buses bring riders to transit stations near shopping and employment centers, but riders then need another transportation mode to reach their final destination, which is known as the last mile problem. A smart bike-sharing system (BSS) can help address this problem and encourage more people to ride public transportation, thus relieving traffic congestion.
At the strategic level, we start with proposing a novel two-layer hierarchical classifier that increases the accuracy of traditional transportation mode classification algorithms. In the transportation sector, researchers can use smartphones to track and obtain information of multi-mode trips. These data can be used to recognize the user's transportation mode, which can be then utilized in several different applications; such as planning new BSS instead of using costly surveys. Next, a new method is proposed to quantify the effect of several factors such as weather conditions on the prediction of bike counts at each station. The proposed approach is promising to quantify the effect of various features on BSSs in cases of large networks with big data. Third, these resulted significant features were used to develop state-of-the-art toolbox algorithms to operate BSSs efficiently at two levels: network and station. Finally, we proposed a quality-of-service (QoS) measurement, namely Optimal Occupancy, which considers the impact of inhomogeneity in a BSS. We used one of toolbox algorithms modeled earlier to estimate the proposed QoS. Results revealed that the Optimal Occupancy is beneficial and outperforms the traditionally-known QoS measurement.
Advisors/Committee Members: Rakha, Hesham A. (committeechair), House, Leanna L. (committeechair), Abbas, Montasir M. (committee member), Yang, Hao (committee member).
Subjects/Keywords: Bike-Sharing System; Quality-of-Service; Transportation Mode Recognition; Urban Computing; Big Data
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APA (6th Edition):
Ashqar, H. I. (2018). Strategic Design of Smart Bike-Sharing Systems for Smart Cities. (Doctoral Dissertation). Virginia Tech. Retrieved from http://hdl.handle.net/10919/97827
Chicago Manual of Style (16th Edition):
Ashqar, Huthaifa Issam. “Strategic Design of Smart Bike-Sharing Systems for Smart Cities.” 2018. Doctoral Dissertation, Virginia Tech. Accessed February 28, 2021.
http://hdl.handle.net/10919/97827.
MLA Handbook (7th Edition):
Ashqar, Huthaifa Issam. “Strategic Design of Smart Bike-Sharing Systems for Smart Cities.” 2018. Web. 28 Feb 2021.
Vancouver:
Ashqar HI. Strategic Design of Smart Bike-Sharing Systems for Smart Cities. [Internet] [Doctoral dissertation]. Virginia Tech; 2018. [cited 2021 Feb 28].
Available from: http://hdl.handle.net/10919/97827.
Council of Science Editors:
Ashqar HI. Strategic Design of Smart Bike-Sharing Systems for Smart Cities. [Doctoral Dissertation]. Virginia Tech; 2018. Available from: http://hdl.handle.net/10919/97827
Virginia Tech
23.
Liu, Qingyu.
Delay-Aware Multi-Path Routing in a Multi-Hop Network: Algorithms and Applications.
Degree: PhD, Computer Engineering, 2019, Virginia Tech
URL: http://hdl.handle.net/10919/90405
► We consider a network modeled as a directed graph, where it takes time for data to traverse each link in the network. It models many…
(more)
▼ We consider a network modeled as a directed graph, where it takes time for data to traverse each link in the network. It models many critical applications both in the communication area and in the transportation field. For example, both the European education network and the US national highway network can be modeled as directed graphs. We consider a scenario where a source node is required to send multiple (a set of) data packets to a destination node through the network as fast as possible, possibly using multiple source-to-destination paths. In this dissertation we study four problems all of which try to figure out routing solutions to send the set of data packets, with an objective of minimizing experienced travel time or subject to travel time constraints. Although all of our four problems are NP-hard, we design approximation algorithms to solve them and obtain solutions with theoretically bounded gaps as compared to the optimal. The first three problems are in the communication area, and the last problem is in the transportation field. We claim the following specific contributions. Minimize maximum delay and average delay. First, we consider the setting of simultaneously minimizing the average travel time and the worst (largest) travel time of sending the set of data packets from source to destination. Existing results say that the two metrics of travel time cannot be minimized to be both within bounded-ratio gaps to the optimal. As a comparison, we design three different routing solutions, each of which can minimize the two metrics of travel time simultaneously within a constant bounded ratio-gap to the optimal, but at a cost of only delivering a portion of the data. Minimize Age-of-Information (AoI). Second, we consider the problem of minimizing a newly proposed travel-time-sensitive performance metric, i.e., AoI, which is the elapsed time since the generation of the last received data. Our AoI study differs from existing ones in that we are the first to consider a set of data and multi-path routing. We develop both an optimal algorithm with a pseudo-polynomial time complexity and an approximation framework with a polynomial time complexity. Maximize network utility. Third, we consider a more general setting with multiple source destination pairs. Each source incurs a utility that is a function of the experienced travel time or the achieved throughput to send data to its destination. Our objective is to maximize the aggregate utility under throughput requirements and travel time constraints. We develop a polynomial-time approximation algorithm, at the cost of violating constraints by up to constant-ratios. It is non-trivial to design such algorithms, as we prove that it is NPcomplete either to construct an optimal solution under relaxed delay constraints or relaxed throughput requirements, or to figure out a feasible solution with all constraints satisfied. Minimize fuel consumption for a heavy truck to timely fulfill multiple transportation tasks. Finally, we consider a truck and multiple transportation…
Advisors/Committee Members: Zeng, Haibo (committeechair), Yang, Yaling (committee member), Rakha, Hesham A. (committee member), Hsiao, Michael S. (committee member), Park, Jung-Min (committee member).
Subjects/Keywords: Delay-Aware Network Flow; Delay-Aware Multi-Path Routing; Multi-Hop Network; Network Resource Allocation; Polynomial-Time Approximation Algorithm
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APA (6th Edition):
Liu, Q. (2019). Delay-Aware Multi-Path Routing in a Multi-Hop Network: Algorithms and Applications. (Doctoral Dissertation). Virginia Tech. Retrieved from http://hdl.handle.net/10919/90405
Chicago Manual of Style (16th Edition):
Liu, Qingyu. “Delay-Aware Multi-Path Routing in a Multi-Hop Network: Algorithms and Applications.” 2019. Doctoral Dissertation, Virginia Tech. Accessed February 28, 2021.
http://hdl.handle.net/10919/90405.
MLA Handbook (7th Edition):
Liu, Qingyu. “Delay-Aware Multi-Path Routing in a Multi-Hop Network: Algorithms and Applications.” 2019. Web. 28 Feb 2021.
Vancouver:
Liu Q. Delay-Aware Multi-Path Routing in a Multi-Hop Network: Algorithms and Applications. [Internet] [Doctoral dissertation]. Virginia Tech; 2019. [cited 2021 Feb 28].
Available from: http://hdl.handle.net/10919/90405.
Council of Science Editors:
Liu Q. Delay-Aware Multi-Path Routing in a Multi-Hop Network: Algorithms and Applications. [Doctoral Dissertation]. Virginia Tech; 2019. Available from: http://hdl.handle.net/10919/90405
Virginia Tech
24.
Yin, Weihao.
An Agent-based Travel Demand Model System for Hurricane Evacuation Simulation.
Degree: PhD, Civil Engineering, 2013, Virginia Tech
URL: http://hdl.handle.net/10919/52344
► This dissertation investigates the evacuees' behavior under hurricane evacuation conditions and develops an agent-based travel demand model system for hurricane evacuation simulation using these behavioral…
(more)
▼ This dissertation investigates the evacuees' behavior under hurricane evacuation conditions and develops an agent-based travel demand model system for hurricane evacuation simulation using these behavioral findings. The dissertation econometrically models several important evacuation decisions including evacuate-stay, accommodation type choice, evacuation destination choice, evacuation mode choice, departure time choice, and vehicle usage choice. In addition, it explicitly considers the pre-evacuation preparation activities using activity-based approach. The models are then integrated into a two-module agent-based travel demand model system.
The dissertation first develops the evacuate-stay choice model using the random-coefficient binary logit specification. It uses heterogeneous mean of the random parameter across households to capture shadow evacuation. It is found that the likelihood of evacuation for households that do not receive any evacuation notice decreases as their distance to coast increase on average. The distance sensitivity factor, or DSF, is introduced to construct the different scenarios of geographical extent of shadow evacuation.
The dissertation then conducts statistical analysis of the vehicle usage choice. It identifies the contributing factors to households' choice of the number of vehicles used for evacuation and develop predictive models of this choice that explicitly consider the constraint imposed by the number of vehicles owned by the household. This constraint is not accommodated by ordered response models. Data comes from a post-storm survey for Hurricane Ivan. The two models developed are variants of the regular Poisson regression model: the Poisson model with exposure and right-censored Poisson regression. The right-censored Poisson model is preferred due to its inherent capabilities, better fit to the data, and superior predictive power. The multivariable model and individual variable analyses are used to investigate seven hypotheses. Households traveling longer distances or evacuating later are more likely to use fewer vehicles. Households with prior hurricane experience, greater numbers of household members between 18 and 80, and pet owners are more likely to use a greater number of vehicles. Income and distance from the coast are insignificant in the multivariable models, although their individual effects have statistically significant linear relationship. However, the Poisson based models are non-linear. The method for using the right-censored Poisson model for producing the desired share of vehicle usage is also provided for the purpose of generating individual predictions for simulation.
The dissertation then presents a descriptive analysis of and econometric models for households' pre-evacuation activities based on behavioral intention data collected for Miami Beach, Florida. The descriptive analysis shows that shopping - particularly food, gasoline, medicine, and cash withdrawal - accounts for the majority of preparation activities, highlighting the importance of…
Advisors/Committee Members: Murray-Tuite, Pamela M. (committeechair), Wernstedt, Kris F. (committee member), Rakha, Hesham A. (committee member), Hancock, Kathleen L. (committee member).
Subjects/Keywords: Hurricane Evacuation; Agent-based Modeling and Simulation; Household Behavior
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APA (6th Edition):
Yin, W. (2013). An Agent-based Travel Demand Model System for Hurricane Evacuation Simulation. (Doctoral Dissertation). Virginia Tech. Retrieved from http://hdl.handle.net/10919/52344
Chicago Manual of Style (16th Edition):
Yin, Weihao. “An Agent-based Travel Demand Model System for Hurricane Evacuation Simulation.” 2013. Doctoral Dissertation, Virginia Tech. Accessed February 28, 2021.
http://hdl.handle.net/10919/52344.
MLA Handbook (7th Edition):
Yin, Weihao. “An Agent-based Travel Demand Model System for Hurricane Evacuation Simulation.” 2013. Web. 28 Feb 2021.
Vancouver:
Yin W. An Agent-based Travel Demand Model System for Hurricane Evacuation Simulation. [Internet] [Doctoral dissertation]. Virginia Tech; 2013. [cited 2021 Feb 28].
Available from: http://hdl.handle.net/10919/52344.
Council of Science Editors:
Yin W. An Agent-based Travel Demand Model System for Hurricane Evacuation Simulation. [Doctoral Dissertation]. Virginia Tech; 2013. Available from: http://hdl.handle.net/10919/52344
Virginia Tech
25.
Elhenawy, Mohammed Mamdouh Zakaria.
Appling Machine and Statistical Learning Techniques to Intelligent Transport Systems: Bottleneck Identification and Prediction, Dynamic Travel Time Prediction, Driver Run-Stop Behavior Modeling, and Autonomous Vehicle Control at Intersections.
Degree: PhD, Computer Engineering, 2015, Virginia Tech
URL: http://hdl.handle.net/10919/73790
► In this dissertation, new algorithms that address three traffic problems of major importance are developed. First automatic identification and prediction algorithms are developed to identify…
(more)
▼ In this dissertation, new algorithms that address three traffic problems of major importance are developed. First automatic identification and prediction algorithms are developed to identify and predict the occurrence of traffic congestion. The identification algorithms concoct a model to identify speed thresholds by exploiting historical spatiotemporal speed matrices. We employ the speed model to define a cutoff speed separating free-flow from congested traffic. We further enhance our algorithm by utilizing weather and visibility data. To our knowledge, we are the first to include weather and visibility variables in formulating an automatic congestion identification model. We also approach the congestion prediction problem by adopting an algorithm which employs Adaptive Boosting machine learning classifiers again something novel that has not been done previously. The algorithm is promising where it resulted in a true positive rate slightly higher than 0.99 and false positive rate less than 0.001.
We next address the issue of travel time modeling. We propose algorithms to model travel time using various machine learning and statistical learning techniques. We obtain travel time models by employing the historical spatiotemporal speed matrices in conjunction with our algorithms. The algorithms yield pertinent information regarding travel time reliability and prediction of travel times. Our proposed algorithms give better predictions compared to the state of practice algorithms.
Finally we consider driver safety at signalized intersections and uncontrolled intersections in a connected vehicles environment. For signalized intersections, we exploit datasets collected from four controlled experiments to model the stop-run behavior of the driver at the onset of the yellow indicator for various roadway surface conditions and multiple vehicle types. We further propose a new variable (predictor) related to driver aggressiveness which we estimate by monitoring how drivers respond to yellow indications. The performance of the stop-run models shows improvements after adding the new aggressiveness predictor. The proposed models are practical and easy to implement in advanced driver assistance systems. For uncontrolled intersections, we present a game theory based algorithm that models the intersection as a chicken game to solve the conflicts between vehicles crossing the intersection. The simulation results show a 49% saving in travel time on average relative to a stop control when the vehicles obey the Nash equilibrium of the game.
Advisors/Committee Members: Besieris, Ioannis M. (committeechair), Rakha, Hesham A. (committeechair), Abbott, Amos L. (committee member), Khedr, Mohamed Essam (committee member), Guo, Feng (committee member).
Subjects/Keywords: Machine learning; statistical learning; ITS; Bottlenecks Identification and Prediction; Dynamic Travel Time Prediction; Stop-run Driver Behavior Modeling; and uncontrolled intersection
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APA (6th Edition):
Elhenawy, M. M. Z. (2015). Appling Machine and Statistical Learning Techniques to Intelligent Transport Systems: Bottleneck Identification and Prediction, Dynamic Travel Time Prediction, Driver Run-Stop Behavior Modeling, and Autonomous Vehicle Control at Intersections. (Doctoral Dissertation). Virginia Tech. Retrieved from http://hdl.handle.net/10919/73790
Chicago Manual of Style (16th Edition):
Elhenawy, Mohammed Mamdouh Zakaria. “Appling Machine and Statistical Learning Techniques to Intelligent Transport Systems: Bottleneck Identification and Prediction, Dynamic Travel Time Prediction, Driver Run-Stop Behavior Modeling, and Autonomous Vehicle Control at Intersections.” 2015. Doctoral Dissertation, Virginia Tech. Accessed February 28, 2021.
http://hdl.handle.net/10919/73790.
MLA Handbook (7th Edition):
Elhenawy, Mohammed Mamdouh Zakaria. “Appling Machine and Statistical Learning Techniques to Intelligent Transport Systems: Bottleneck Identification and Prediction, Dynamic Travel Time Prediction, Driver Run-Stop Behavior Modeling, and Autonomous Vehicle Control at Intersections.” 2015. Web. 28 Feb 2021.
Vancouver:
Elhenawy MMZ. Appling Machine and Statistical Learning Techniques to Intelligent Transport Systems: Bottleneck Identification and Prediction, Dynamic Travel Time Prediction, Driver Run-Stop Behavior Modeling, and Autonomous Vehicle Control at Intersections. [Internet] [Doctoral dissertation]. Virginia Tech; 2015. [cited 2021 Feb 28].
Available from: http://hdl.handle.net/10919/73790.
Council of Science Editors:
Elhenawy MMZ. Appling Machine and Statistical Learning Techniques to Intelligent Transport Systems: Bottleneck Identification and Prediction, Dynamic Travel Time Prediction, Driver Run-Stop Behavior Modeling, and Autonomous Vehicle Control at Intersections. [Doctoral Dissertation]. Virginia Tech; 2015. Available from: http://hdl.handle.net/10919/73790
Virginia Tech
26.
Arat, Mustafa Ali.
Development and Improvement of Active Vehicle Safety Systems by Means of Smart Tire Technology.
Degree: PhD, Mechanical Engineering, 2013, Virginia Tech
URL: http://hdl.handle.net/10919/51618
► The dynamic behavior of a vehicle is predominantly controlled by the forces and moments generated at the contact patch between the tire and the road…
(more)
▼ The dynamic behavior of a vehicle is predominantly controlled by the forces and moments generated at the contact patch between the tire and the road surface. As a result, tire characteristics can dramatically change vehicle response, especially during maneuvers that yields the tires to reach to the limits of its adhesion capacity. To assist the driver in such cases and to prevent other possible instability scenarios, various vehicle control systems e.g. anti-lock brakes (ABS), stability controllers (ESP, ESC) or rollover mitigation schemes are introduced, which are generally known as active vehicle safety systems. Based on the above facts, one can easily come to the conclusion that to improve upon the current control algorithms developed for the technology in use; a vehicle control system design requires accurate knowledge of the tire states. This study proposes the use of a smart tire system that can provide information on momentary variation of tire features through the sensor units attached directly on the tire and develops control algorithms based on this information to assure the match-up between tire and controller dynamics. A prototype smart tire system was developed for field testing and for detailed analysis of its potential. Based on the collected prototype data, novel observer and controller schemes were developed to obtain dynamic tire state information and to improve vehicle handling performance. The proposed algorithms were implemented and evaluated using numerical analysis in Matlab/SimulinkR environment. For a more realistic simulation environment, vehicle models were integrated from Mechanical Simulations CarSimR® software suite.
Advisors/Committee Members: Taheri, Saied (committeechair), Ahmadian, Mehdi (committee member), Ferris, John B. (committee member), West, Robert L. (committee member), Rakha, Hesham A. (committee member).
Subjects/Keywords: Active Vehicle Safety Systems; Smart/Intelligent Tire; Adaptive Control; Optimization; Nonlinear Systems
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APA (6th Edition):
Arat, M. A. (2013). Development and Improvement of Active Vehicle Safety Systems by Means of Smart Tire Technology. (Doctoral Dissertation). Virginia Tech. Retrieved from http://hdl.handle.net/10919/51618
Chicago Manual of Style (16th Edition):
Arat, Mustafa Ali. “Development and Improvement of Active Vehicle Safety Systems by Means of Smart Tire Technology.” 2013. Doctoral Dissertation, Virginia Tech. Accessed February 28, 2021.
http://hdl.handle.net/10919/51618.
MLA Handbook (7th Edition):
Arat, Mustafa Ali. “Development and Improvement of Active Vehicle Safety Systems by Means of Smart Tire Technology.” 2013. Web. 28 Feb 2021.
Vancouver:
Arat MA. Development and Improvement of Active Vehicle Safety Systems by Means of Smart Tire Technology. [Internet] [Doctoral dissertation]. Virginia Tech; 2013. [cited 2021 Feb 28].
Available from: http://hdl.handle.net/10919/51618.
Council of Science Editors:
Arat MA. Development and Improvement of Active Vehicle Safety Systems by Means of Smart Tire Technology. [Doctoral Dissertation]. Virginia Tech; 2013. Available from: http://hdl.handle.net/10919/51618
Virginia Tech
27.
Jahangiri, Arash.
Investigating Violation Behavior at Intersections using Intelligent Transportation Systems: A Feasibility Analysis on Vehicle/Bicycle-to-Infrastructure Communications as a Potential Countermeasure.
Degree: PhD, Civil Engineering, 2015, Virginia Tech
URL: http://hdl.handle.net/10919/76729
► The focus of this dissertation is on safety improvement at intersections and presenting how Vehicle/Bicycle-to-Infrastructure Communications can be a potential countermeasure for crashes resulting from…
(more)
▼ The focus of this dissertation is on safety improvement at intersections and presenting how Vehicle/Bicycle-to-Infrastructure Communications can be a potential countermeasure for crashes resulting from drivers' and cyclists' violations at intersections. The characteristics (e.g., acceleration capabilities, etc.) of transportation modes affect the violation behavior. Therefore, the first building block is to identify the users' transportation mode. Consequently, having the mode information, the second building block is to predict whether or not the user is going to violate. This step focuses on two different modes (i.e., driver violation prediction and cyclist violation prediction). Warnings can then be issued for users in potential danger to react or for the infrastructure and vehicles so they can take appropriate actions to avoid or mitigate crashes.
A smartphone application was developed to collect sensor data used to conduct the transportation mode recognition task. Driver violation prediction task at signalized intersections was conducted using observational and simulator data. Also, a naturalistic cycling experiment was designed for cyclist violation prediction task. Subsequently, cyclist violation behavior was investigated at both signalized and stop-controlled intersections. To build the prediction models in all the aforementioned tasks, various Artificial Intelligence techniques were adopted. K-fold Cross-Validation as well as Out-of-Bag error was used for model selection and validation.
Transportation mode recognition models contributed to high classification accuracies (e.g., up to 98%). Thus, data obtained from the smartphone sensors were found to provide important information to distinguish between transportation modes. Driver violation (i.e., red light running) prediction models were resulted in high accuracies (i.e., up to 99.9%). Time to intersection (TTI), distance to intersection (DTI), the required deceleration parameter (RDP), and velocity at the onset of a yellow light were among the most important factors in violation prediction. Based on logistic regression analysis, movement type and presence of other users were found as significant factors affecting the probability of red light violations by cyclists at signalized intersections. Also, presence of other road users and age were the significant factors affecting violations at stop-controlled intersections. In case of stop-controlled intersections, violation prediction models resulted in error rates of 0 to 10 percent depending on how far from the intersection the prediction task is conducted.
Advisors/Committee Members: Dingus, Thomas A. (committeechair), Rakha, Hesham A. (committeechair), Elshawarby, Ihab E. (committee member), Doerzaph, Zachary R. (committee member).
Subjects/Keywords: Intersection safety; driver/cyclist violation prediction; transportation mode recognition; machine learning
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APA (6th Edition):
Jahangiri, A. (2015). Investigating Violation Behavior at Intersections using Intelligent Transportation Systems: A Feasibility Analysis on Vehicle/Bicycle-to-Infrastructure Communications as a Potential Countermeasure. (Doctoral Dissertation). Virginia Tech. Retrieved from http://hdl.handle.net/10919/76729
Chicago Manual of Style (16th Edition):
Jahangiri, Arash. “Investigating Violation Behavior at Intersections using Intelligent Transportation Systems: A Feasibility Analysis on Vehicle/Bicycle-to-Infrastructure Communications as a Potential Countermeasure.” 2015. Doctoral Dissertation, Virginia Tech. Accessed February 28, 2021.
http://hdl.handle.net/10919/76729.
MLA Handbook (7th Edition):
Jahangiri, Arash. “Investigating Violation Behavior at Intersections using Intelligent Transportation Systems: A Feasibility Analysis on Vehicle/Bicycle-to-Infrastructure Communications as a Potential Countermeasure.” 2015. Web. 28 Feb 2021.
Vancouver:
Jahangiri A. Investigating Violation Behavior at Intersections using Intelligent Transportation Systems: A Feasibility Analysis on Vehicle/Bicycle-to-Infrastructure Communications as a Potential Countermeasure. [Internet] [Doctoral dissertation]. Virginia Tech; 2015. [cited 2021 Feb 28].
Available from: http://hdl.handle.net/10919/76729.
Council of Science Editors:
Jahangiri A. Investigating Violation Behavior at Intersections using Intelligent Transportation Systems: A Feasibility Analysis on Vehicle/Bicycle-to-Infrastructure Communications as a Potential Countermeasure. [Doctoral Dissertation]. Virginia Tech; 2015. Available from: http://hdl.handle.net/10919/76729
Virginia Tech
28.
Noble, Alexandria M.
Safety, Operational, and Energy Impacts of In-Vehicle Adaptive Stop Displays Using Connected Vehicle Technology.
Degree: MS, Civil Engineering, 2015, Virginia Tech
URL: http://hdl.handle.net/10919/51216
► Driving through an un-signalized intersection creates multiple opportunities for missed or misunderstood information. Stop signs, in particular, can be stolen, covered by vegetation, or rotated…
(more)
▼ Driving through an un-signalized intersection creates multiple opportunities for missed or misunderstood information. Stop signs, in particular, can be stolen, covered by vegetation, or rotated out of place, leading to an absence of information, contributing to inappropriate decision-making and crashes. Stop controlled intersections have also been shown to be a source of unnecessary delay and emissions due to their frequent, often inappropriate use. Using connected vehicle technology, it is possible to place an electronic stop sign within the vehicle that tells the driver to stop when a conflict in the intersection is imminent, thus reducing the probability of missed information by the driver, and decreasing the amount of unnecessary delay, fuel consumption, and emissions. Before implementing any new technology, it is important to assess it from both a transportation engineering and human factors standpoint to assess the value of the system.
The objective of this study was to assess several key benefits of an adaptive in-vehicle stop display as well as to determine if there are any negative safety implications with the use of this system. This assessment was accomplished through a test track experiment where participants experienced conditions where a standard R1-1 stop sign was displayed on the in-vehicle display, as well as an experimental sign, which informed them to proceed through the intersection with caution. Data collected from in-vehicle sensors was analyzed, and results indicate that the implementation of this technology reduces delay, decreases fuel consumption, and does not instigate any safety decrements.
Advisors/Committee Members: Dingus, Thomas A. (committeechair), Rakha, Hesham A. (committeechair), Katz, Bryan J. (committee member), Doerzaph, Zachary R. (committee member).
Subjects/Keywords: Intersection; safety; stop sign; un-signalized intersection; connected vehicles; Adaptive Stop Display; in-vehicle
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APA (6th Edition):
Noble, A. M. (2015). Safety, Operational, and Energy Impacts of In-Vehicle Adaptive Stop Displays Using Connected Vehicle Technology. (Masters Thesis). Virginia Tech. Retrieved from http://hdl.handle.net/10919/51216
Chicago Manual of Style (16th Edition):
Noble, Alexandria M. “Safety, Operational, and Energy Impacts of In-Vehicle Adaptive Stop Displays Using Connected Vehicle Technology.” 2015. Masters Thesis, Virginia Tech. Accessed February 28, 2021.
http://hdl.handle.net/10919/51216.
MLA Handbook (7th Edition):
Noble, Alexandria M. “Safety, Operational, and Energy Impacts of In-Vehicle Adaptive Stop Displays Using Connected Vehicle Technology.” 2015. Web. 28 Feb 2021.
Vancouver:
Noble AM. Safety, Operational, and Energy Impacts of In-Vehicle Adaptive Stop Displays Using Connected Vehicle Technology. [Internet] [Masters thesis]. Virginia Tech; 2015. [cited 2021 Feb 28].
Available from: http://hdl.handle.net/10919/51216.
Council of Science Editors:
Noble AM. Safety, Operational, and Energy Impacts of In-Vehicle Adaptive Stop Displays Using Connected Vehicle Technology. [Masters Thesis]. Virginia Tech; 2015. Available from: http://hdl.handle.net/10919/51216
Virginia Tech
29.
Aljamal, Mohammad Abdulraheem.
Real-Time Estimation of Traffic Stream Density using Connected Vehicle Data.
Degree: PhD, Civil Engineering, 2020, Virginia Tech
URL: http://hdl.handle.net/10919/100149
► Estimating the number of vehicles (vehicle counts) on a road segment is crucial in advanced traffic management systems. However, measuring the number of vehicles on…
(more)
▼ Estimating the number of vehicles (vehicle counts) on a road segment is crucial in advanced
traffic management systems. However, measuring the number of vehicles on a road segment
in the field is difficult because of the need for installing multiple detection sensors in that
road segment. In this dissertation, several estimation approaches are developed to estimate
the number of vehicles on signalized roadways using connected vehicle (CV) data. The
CV is defined as the vehicle that can share its instantaneous location every time t. The
dissertation develops model-driven approaches, such as a linear Kalman filter (KF), a linear
adaptive KF (AKF), and a nonlinear Particle filter (PF), to estimate the number of vehicles
using CV data only. The proposed model-driven approaches are evaluated using real and
simulated data, the former of which were collected along a signalized roadway in downtown
Blacksburg, VA. Results indicate that the number of vehicles produced by the linear KF
approach is the most accurate. The results also show that the KF approach is the least
sensitive approach to the initial conditions. Machine learning approaches are also developed
to estimate the number of vehicles, such as an artificial neural network (ANN), a k-nearest
neighbor (k-NN), and a random forest (RF). The machine learning approaches also use CV
data only. Results demonstrate that the ANN approach outperforms the k-NN and RF
approaches. Finally, the dissertation compares the performance of the model-driven and the
machine learning approaches, showing that the ANN approach produces the most accurate
estimates. However, taking into consideration the computational time needed to train the
ANN approach, the huge amount of data needed, and the uncertainty in the performance
when new traffic behaviors are observed (e.g., incidents), the use of the KF approach is
highly recommended in the application of vehicle count estimation due to its simplicity and
applicability in the field.
Advisors/Committee Members: Rakha, Hesham A. (committeechair), Heaslip, Kevin Patrick (committee member), Hotle, Susan (committee member), Du, Jianhe (committee member).
Subjects/Keywords: Real-Time Estimation; Connected Vehicles; Traffic Density; Machine Learning; Kalman Filter; Particle Filter; Artificial Neural Network; Random Forest; k-Nearest Neighbors; Level of Market Penetration Rate
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APA ·
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MLA ·
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APA (6th Edition):
Aljamal, M. A. (2020). Real-Time Estimation of Traffic Stream Density using Connected Vehicle Data. (Doctoral Dissertation). Virginia Tech. Retrieved from http://hdl.handle.net/10919/100149
Chicago Manual of Style (16th Edition):
Aljamal, Mohammad Abdulraheem. “Real-Time Estimation of Traffic Stream Density using Connected Vehicle Data.” 2020. Doctoral Dissertation, Virginia Tech. Accessed February 28, 2021.
http://hdl.handle.net/10919/100149.
MLA Handbook (7th Edition):
Aljamal, Mohammad Abdulraheem. “Real-Time Estimation of Traffic Stream Density using Connected Vehicle Data.” 2020. Web. 28 Feb 2021.
Vancouver:
Aljamal MA. Real-Time Estimation of Traffic Stream Density using Connected Vehicle Data. [Internet] [Doctoral dissertation]. Virginia Tech; 2020. [cited 2021 Feb 28].
Available from: http://hdl.handle.net/10919/100149.
Council of Science Editors:
Aljamal MA. Real-Time Estimation of Traffic Stream Density using Connected Vehicle Data. [Doctoral Dissertation]. Virginia Tech; 2020. Available from: http://hdl.handle.net/10919/100149
Virginia Tech
30.
Tarhini, Hussein Ali.
Network Models In Evacuation Planning.
Degree: PhD, Industrial and Systems Engineering, 2014, Virginia Tech
URL: http://hdl.handle.net/10919/64359
► This dissertation addresses the development and analysis of optimization models for evacuation planning. Specifically we consider the cases of large-scale regional evacuation using household vehicles…
(more)
▼ This dissertation addresses the development and analysis of optimization models for evacuation planning. Specifically we consider the cases of large-scale regional evacuation using household vehicles and hospital evacuation.
Since it is difficult to estimate the exact number of people evacuating, we first consider the case where the population size is uncertain. We review the methods studied
in the literature, mainly the strategy of using a deterministic counterpart, i.e., a single deterministic parameter to represent the uncertain population, and we show that these
methods are not very effective in generating a good traffic management strategy. We provide alternatives, where we describe some networks where an optimal policy exist independent of the demand realization and we propose some simple heuristics for more complex ones.
Next we consider the traffic management tools that can be generated from an evacuation plan. We start by introducing the cell transmission model with flow reduction. This model captures the flow reduction after the onset of congestion. We then discuss the management tools that can be extracted from this model. We also propose some simplification to the model formulation to enhance its tractability. A heuristic for generating a solution is also proposed, and its solution quality is analyzed.
Finally, we discuss the hospital evacuation problem where we develop an integer programming model that integrates the building evacuation with the transportation of patients. The impact of building evacuation capabilities on the transportation plan is investigated through the case of a large regional hospital case study. We also propose a decomposition scheme to improve the tractability
of the integer program.
Advisors/Committee Members: Bish, Douglas R. (committeechair), Bish, Ebru K. (committee member), Pasupathy, Raghu (committee member), Rakha, Hesham A. (committee member).
Subjects/Keywords: Cell Transmission Model (CTM); dynamic traffic assignment; evacuation planning; hospital evacuation
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APA (6th Edition):
Tarhini, H. A. (2014). Network Models In Evacuation Planning. (Doctoral Dissertation). Virginia Tech. Retrieved from http://hdl.handle.net/10919/64359
Chicago Manual of Style (16th Edition):
Tarhini, Hussein Ali. “Network Models In Evacuation Planning.” 2014. Doctoral Dissertation, Virginia Tech. Accessed February 28, 2021.
http://hdl.handle.net/10919/64359.
MLA Handbook (7th Edition):
Tarhini, Hussein Ali. “Network Models In Evacuation Planning.” 2014. Web. 28 Feb 2021.
Vancouver:
Tarhini HA. Network Models In Evacuation Planning. [Internet] [Doctoral dissertation]. Virginia Tech; 2014. [cited 2021 Feb 28].
Available from: http://hdl.handle.net/10919/64359.
Council of Science Editors:
Tarhini HA. Network Models In Evacuation Planning. [Doctoral Dissertation]. Virginia Tech; 2014. Available from: http://hdl.handle.net/10919/64359
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Open Access Theses and Dissertations
